Art. V.—Osteology of* Eremophila alpestris. 
By R. W. Slmfcldt, Acting Assistant Surgeon United States 
Army. 
The 11th of March, 1880, was a particularly severe day at Fort Fetter- 
man.* A violent wind and snow storm prevailed during the entire 
twenty-four hours. In the creek bottom, below the fort, where the wind 
had exposed the ground of some laud that had been used for gardening 
purposes the year before, thousands of Horned Larks congregated. 
They seemed disinclined to vacate their partially sheltered position, pre- 
ferring to face the few death-dealing fires I delivered them rather than 
be tossed over the prairie by the freezing storm. At each shot, the flocks 
arose, skimmed low over the ground, soon to alight again. These sim- 
ple manoeuvres afforded me abundant opportunity to secure many speci- 
mens, and several hundred were taken. As they afterwards lay upon 
the table in my study, one would almost have said, before submitting 
them to careful scrutiny and examination, that not only was true alpes- 
tris represented, but both the varieties, leucolccma and chrysolcema, de- 
scribed by modern writers. Certainly it was that there were many 
shades of their normal coloring among them, accompanied by differ- 
ences in size that were not due to sex. I feel sure my reader will par- 
don the liberty I take in adding to an article upon the osteology of this 
interesting bird a life-size portrait of it, selected from the large number 
before me on the occasion referred to. The hind claw in this individual 
(PI. IY, Fig. 22) was longer and straighter than any of the others ex- 
amined by me, but this member, as well as the areas of the different col- 
ors of its plumage, are, in my representation, the results of careful meas- 
urements and comparison. I have never seen the black pectoral crescent 
of this bird in the low position in which Audubon represents it in his 
work (B. Am., YIII, FTo. 100, PI. 497), where he figures his Alauda 
rufa, the Western Shore Lark. The bird figured in my plate was taken 
in that section of our country where the variety leucolcema is usually 
found breeding during the season, and probably belongs to series de- 
scribed as such, but certainly has attained a style and brilliancy of col- 
oring that brings it very near to true alpestris, its size excluding it from 
the variety chrysolcema. Interesting and important as this part of the 
subject is in the life history of this bird, we must, with these few re- 
* Wyoming Territory, United States, lat. 42° 23' 35" N., long. 105° 21' 4" W. 
119 120 
BULLETIN UNITED STATES GEOLOGICAL SUEVEY. f Voi:VI. 
marks, allow it to rest here and proceed with the true object of this 
paper, a description of its skeleton, simply reminding the student that 
of all the several genera that go to make up the family Alaudidce, or 
Larks, but one genus has fallen to the lot of the North American fauna, 
and that the genus contains but one species, with its varieties, the oste- 
ology of that species being the subject of the present article. 
The slcull—(Pl. IY, Figs. 22,25, and 2G).—It is a striking characteristic 
in the skulls of nearly all adult birds that certain bones become firmly 
united, their sutures entirely disappearing; perhaps in no species of the 
highly organized suborder Oscines has this almost universal avian feature 
been so thoroughly carried out as in our present subject, the Horned 
Lark. Occasionally we do find, however, a trace to guide us in locating 
the original boundaries of the primitive elements, even among the Os- 
cines, as the sutures, amidst the parietals and frontals in the cranium of 
Lamms, when maceration is carried to a high degree, but in Eremophila, 
as already stated, there is a total absence of any such indication. If we 
remove the lower mandible from the skull in any of the class Ares, and 
place the remainder on the horizontal plane, with the basi-cranii down- 
wards, we observe that in different skulls there exists in this position 
differences in equilibrium, and differences in, what wTe will call, the an- 
terior and posterior hearing points, or the points upon which this part 
skull we are studying, we find, when it is placed as directed above, 
of the skull rests on the horizontal plane. To illustrate this in the 
that its equilibrium is quite stable, and that it rests posteriorly upon 
the tympanies, anteriorly upon the till of the superior mandible, which 
constitute, respectively, its posterior and anterior bearing points. In 
this case there is but one anterior bearing point, with two posterior 
ones. This is a very common result, but there are at the same time 
many exceptions to it, as in Numenius and many species of the family 
Anatidce. 
Again, if we erect a perpendicular from one of the posterior bearing 
points, or the posterior bearing point, for sometimes it is the condyle, 
we find that the planes passing through the circumference of the fora- 
men magnum and the occipital vertebra, and the point where the foot 
of this perpendicular and the posterior bearing points coincide, make 
certain angles with the horizontal plane (the ordinary horn protractor 
is the best instrument to take these angles with), which wTe will call, re- 
spectively, the angle of the foramen and the angle of the base. These two 
angles, in many instances, practically coincide, as in our Lark, wdiere 
they make an angle of 40° with the horizontal plane. In the cut, II IP 
is the horizontal plane ; a the anterior and p the posterior bearing points. 
These angles also differ in many birds •, e.g., the anterior bearing 
point in Ardea herodias is the tip of the upper mandible, the posterior 
ones being the inner of the three facets on each tympanic; the angles 
of the planes of the base and foramen about coincide, and is 50°. In 
many of the Owls and diurnal birds of prey, the bearing points being 121 
Vo. 5.] SHUFELDT ON THE OSTEOLOGY OF EREMOPHILA. 
the same as in the last example (it being, however, the inner facet of 
two on the tympanies, as a rule), the combined angles, or either of them 
separately, is very small, or the base and foramen may be found to lie 
nearly in a plane parallel to the plane upon which the skull rests, or the 
angles are o°. We see then that in the present case, the bearing points 
being given, the angle of the combined planes is 40°, which fact, even 
without actually taking the angles in question, conveys to our minds 
about the “pitch” or relation of the basi-cranii to the other salient fea- 
tures of the skull. Taken accurately, these angles, it is obvious, would 
have a certain value when we come to compare the various skulls of the 
elass. 
The primary elements of the occipital, or first cranial vertebra, have 
become completely fused together, and with such other bony elements of 
the vertebra beyond, of the mesencephalic arch, with which they usually 
articulate. The well-marked superior curved line that limits muscular 
attachment above would seem to be, and in all probability is, about the 
position of the lambdoid suture, and the superior boundary of the bone 
we are describing. This curved line descends and is gradually lost along 
the boundaries of the mastoids and occipitals on either side. Exter- 
nally and inferiorly we find the occipital pierced by the usual foramina 
of the basi-cranii. The group for the exit of the eighth pair of nerves, 
beingthe most anterior of all, are situated on either side, in well-marked 
depressions or pits, some 7 millimetres apart. Back of these and nearer 
together are the minute precondyloids, looking forwards and outwards for 
the passage of the hypoglossal nerves. These last foramina are just an- 
terior to the border of foramen magnum; this latter aperture is of good 
size, comparatively, having antero-posterior and transverse diameters 
of 3 millimetres each, with an additional millimetre for the oblique 
diameters, making the latter 4 millimetres each. It is subcircular in 
outline, its anterior rim passing around a depression that lies just in 
front of the condyle, giving the latter the appearance of jutting out 
into the foraminal space. The condyle is nearly sessile, having the 
merest trace of a neck, hemispheroidal in form, with an horizontal 122 
BULLETIN UNITED STATES GEOLOGICAL SURVEY. [FoJ.YI. 
and average diameter of .5 of a millimetre. Above and midway, later- 
ally, the borders of the foramen are encroached upon by the petrosal on 
either side, giving it rather a constricted appearance; from these points, 
as we follow the posterior moiety of the foraminal periphery, we find it 
to be grooved, each groove ending posteriorly within a millimetre of each 
other, in a minute foramen that traverses the internal table of the cra- 
nium upwards, outwards, and forwards for a short distance, thence to 
arch around, as a sinus, the epencephalic fossa, meet in the longitu- 
dinal sinus coming from above. This arrangement obtains in the Cor- 
vidce, and some other families, where it is more strongly marked. The 
diapoxfhyses of the occipital vertebrae are in a plane but a little lower 
than the basi-sphenoid; they form, as is quite common, the horizontal 
floor of the cavity of the otocrane, and blend with the surrounding bones. 
A moderately well-marked u cerebellar prominence*77 occupies its usual 
site in the middle line; no openings or foramina are ever to be discovered 
either at its summit or laterally, as seen in some other birds (Anatidce, 
>S'trigidw). It divides the shallow temporal fossae that slope away from 
it on either side, and varies somewhat in size in different individuals. 
From the upper region of the ear and the superior boundaries of the tem- 
poral fossae to the line of that psuedo-articulation, the frouto-mandibu- 
lar, this bird7s cranium is remarkably smooth, and of a clear white, and, 
owing to the extraordinary amount of diploic tissue, possessing a pe- 
culiar translucency. The median furrow is only well marked as it passes 
between the orbits; the superior peripheries of these cavities, as con- 
stituting one of the boundaries of the surface under consideration, are 
sharp at first, rounding as they include the lachrymals, and entirely de- 
void of any notches or indentations. As is usual, all sutural ti aces are 
absent (PI. IY. Fig. 25). The transverse line of the fronto-mandibular 
Juncture is slightly concave backwards along its middle third, the extremi- 
ties sloping a little downwards and backwards. The joint motion is 
only moderately free. No well-marked suture defines its exact locality, 
as in Harporhynchus and others. The bones that go to form the supe- 
rior mandible, both above and below, are mutually confluent at all their 
usual points of contact and articulations, with complete obliteration of 
their original borders. The nearly perpendicular nasals on either side 
form the anterior boundary of a triangular opening, of which the lachry- 
mals and maxillaries form, respectively, the posterior boundary and base. 
These triangles are not complete, insomuch as the lachrymals do not 
meet the infraorbital bars at the inferior and inner angles. They lead 
into the rhinal vacuity on either side. It must be borne well in mind 
by the reader that in describing the upper mandible in the skulls of all 
birds, it invariably presupposes the removal of its horny integumental 
sheath that it wears during life, and gives to this portion of the cra- 
nium a vastly different shape. Either tomial edge is curved and quite 
sharp; their anterior mergence, or point of the beak, is decidedly rounded, 
and fully a millimetre in width. No. 5.1 SHUFELDT ON THE OSTEOLOGY OF EREMOPHILA. 
123 
The superior mandible is rather broad at its base ; the culmen, origi- 
nating in a flattened space just anterior to the fronto-mandibular artic- 
ulation, is rounded throughout its extent and gently curved downwards,, 
while below, the line joining the middle points of the bases of the triangles 
above mentioned, averages 7 millimetres in length. The sides of the in- 
ter-maxillary are smooth,presenting only occasionally a row of very mi- 
nute foramina for examination ; sometimes a faint suture shows itself on 
either side, extending almost down to the nostril, between this bone and 
each nasal. Beneath, the palatine fissure is broad and rounded ante- 
riorly, the roof of the mouth beyond being gently concave and grooved 
mesially for its entire length, and marked by a few foramina. The ex- 
ternal apertures of the nostrils are quite large, nearly elliptical in out- 
line, approaching each other within less than .5 of a millimetre above. 
Their borders, formed by the nasals behind, are sharp; anterior, more 
rounded. The major axes of these openings average 4 millimetres, 
the corresponding minor axes 3 millimetres. The planes passed through 
their peripheries look upward, outward, and forward. The nasals are 
fan-shaped, both above and below, the expansion being slightly twisted,, 
in order to accommodate themselves to the form of the bill. The broad 
lachrymals, assisted by the prefrontal, effectually separate the orbital 
vacuities from the rhinal chambers. The latter are remarkably open, 
owing to the size in the skull of the various apertures leading into 
them from without, already described, and devoid of all septa or bony 
offshoots, although the prefrontal, intermaxillary, and palatines together 
occasionally develop irregularly formed ethmo-turbinals, that extend into 
this space from behind and afford the necessary surface for the pitui- 
tary membrane. But there is nothing that has the slightest semblance 
to an osseus septum narium. The anterior olfactory foramina, narrow 
slits one millimetre long, are found between the lachrymals and pre- 
frontal, close to the vertical septum of the latter; their outer extremi- 
ties being the superior, they are seen to look downward and forward 
as they open into the nasal cavities from the bases of the concavities, 
formed by the bones above mentioned. 
The orbital cavities are capacious, having rather a forward look; at 
the same time they look a little downward. Their limiting borders are 
ovate in outline, with the greater end backward, being incomplete be- 
low. Anteriorly the septum that divides them is remarkably entire and 
of considerable thickness; posteriorly and above there exists quite a 
deficiency, of a shape shown in PI. IY, Fig. 22; this is situated just in 
front of the large quadrilateral rhinencephalic foramen, and allows a good 
passage from either orbit into the brain-case. The same condition ob- 
tains below with the opening for the exit of the optic nerves, only the 
latter is much smaller and quite circular; to its outer side there are 
several minute foramina that lead directly into the brain-case. The 
groove for the first pair is distinct anteriorly on either side, and opens, 
into slits between the prefrontal and lachrymals, similar to those described 124 
BULLETIN UNITED STATES GEOLOGICAL SURVEY. [FoI.YL 
when speaking of them in connection with the nasal cavities. These, 
the anterior rhinal foramina, together seem to he the homologue of the 
u cribriform plate ”of anthropotomy. The anterior wall of an orbit is 
formed by a lachrymal; this bone is larger than usually found in avian 
crania of this size. It is quadrilateral in form, concave posteriorly, thor- 
oughly confluent with the frontal, nasal, and ethmoid, but not coming 
in contact either with, the palatines or suborbital style. About the mid- 
dle of its outer border it presents a rounded notch for the lacrymal duct. 
Its anterior surface, forming the posterior wall for the rhinal vacuity, is 
undulating, though generally convex. 
The superior wall of the orbit is narrow, gently concave, and formed 
as usual by the frontal. It looks downwards and outwards and merges 
into the orbito-cranial septum behind, conformably with the shape of the 
cavity under consideration. The posterior wall of the orbit presents 
quite a number of interesting points for examination. Internally and 
above we find the posterior rhinal foramen, and below it the foramen 
opticus, already described. In addition to other minute openings men- 
tioned above, we have the foramen ovale, occupying a lower plane than 
any of the others, and situated more external to them, being almost di- 
rectly behind the orbital process of the tympanic. Above it we observe 
a thin circular convexity, indicating the locality of the mesencephalic 
fossa •, this sometimes develops at its outer border a sharp, vertical, 
osseous spine or plate, that points downwards, forwards, and inwards 
into the orbital cavity. Still beyond this, outwardly, we find another 
process, or rather two processes combined, with an elliptical foramen 
between them, placed vertically. The inner portion consists of a square 
lamina of bone, looking upwards and forwards ; the other smaller and 
outer portion is a trihedral spine that descends, apparently from the 
frontal, to meet its external margin. The arrangement gives to the en- 
tire posterior wall a certain facing, directly forward, forcing upon the 
cranium of this little bird an aspect peculiar to another family, from which 
it is far removed—the Strigidce. 
The osseous floor of the orbital cavity is always more or less imperfect 
throughout the class, and is here formed by the customary bones, the 
tympanic, pterygoid, slightly by the lachrymal, and limited externally by 
the malo-maxillary squamosal bar. 
The palatines nowhere come in contact with each other, and the pala- 
tine fissure is very wide, broadly rounded at both ends. The anterior 
extremity of each of these bones articulates in the usual manner, im- 
movable, with the maxillary and intermaxillary. Back from this point 
as far as the under surface of the lachrymals, on either side, they are but 
very slender, straight, and horizontally flattened little bones, without 
plate or process; at this latter point they suddenly expand into quadrate 
posterior ends, each slightly inclined downwards towards the median 
plane, throwing out a thin, nearly vertical plate for articulation with 
the fan-like and anterior ends of the pterygoids, while rnesially they de- No. 5.1 SHUFELDT ON THE OSTEOLOGY OF EREMOPHILA. 
125 
velop two other slender horizontal plates, the superior one being pro- 
longed forward as a fine spicula of bone to meet the ethmo-turbinal mass, 
as above described. 
They lightly touch the rostrum of the sphenoid, in company with the 
pterygoids, forming the usual arthrodial joint at this point in avian 
structure. Above they are smooth, look upwards and outwards, and 
form a portion of the floor of the orbit on either side. The union among 
the basi-presphenoidal process, vomerine, and prefrontal plates is com- 
plete, all sutural traces having disappeared, and the included bones form 
the interorbital septum as already described. The zygomatic style? 
very slender, straight, and throughout its continuity nearly of uniform 
calibre, descends from before backwards from its maxillary articulation 
to the tympanic, about 4 millimetres, the skull being horizontal. 
The coalescence among its three original elements is unusually per- 
fect. Its anterior horizontal expansion is very slight, being crowded 
towards the intermaxillary osseous tomium on either side by the widely 
separated palatines. 
Its posterior extremity is club-shaped and turned upwards, bearing 
on its inner aspect a hemispheroidal articular facette for the cotyloid 
cavity of the tympanic. In no single articulation found in the skeleton 
throughout the class does there seem to be more variation in plan, to 
meet the same end and carry out the same function, than we find in the 
pterygo-palatine with the rostrum of the basi-sphenoid. 
In our present subject, as in Pica and Corvus and many others, this 
extremity bears a thin expansion that articulates by its anterior edge 
with the j>alatine plate and neatly grasps the rounded and inferior side 
of the rostrum, the two bones not usually coming in contact. The 
shaft of the pterygoid also slightly expands horizontally just before this 
articular surface is developed, more particularly in the angle between 
the two, adding greatly to the strength of the bone, and somewhat to 
the floor of the cavity of the orbit. The angle of divergence of the 
pterygoids in 'the present instance is exactly 45°; the intertympanic 
chord, 7 millimetres. The shaft of this bone is comparatively slender, 
prismoidal in form, somewhat twisted, and develops among the older 
birds sharp projecting edges. The enlarged tympanic extremity bears 
a subelliptical articulating facette, that glides upon a similarly formed 
surface surmounting the pterygoidal process at the base of the orbital 
process of the corresponding tympanic element. These two little bones 
are well separated from the basi-sphenoid, and never any evidence of 
the development of pterapophysial processes is to be observed. As is 
generally, though by no means universally, the case among birds, the 
mastoid process of the tympanic in this Lark is distinctly bifid, each 
limb presenting for examination at its extremity an elliptical convex 
facette for articulation in a cup-shaped cavity intended for its reception 
in the roof of the aural vacuity. Of the two surfaces, the outer and at 
the same time the anterior looks outwards, forwards, and upwards, while 126 
BULLETIN UNITED STATES GEOLOGICAL SURVEY. [VoI.YI. 
the inner and posterior one, surmounting the shorter limb or bifurcation, 
looks backwards and upwards. These two projections of the mastoid 
process are further separated xmsteriorly by a deep non-articular de- 
pression. The orbital process is well developed, long and slender, ter- 
minating in a knobbed extremity, the whole extending well within the 
orbital space. It has at its base, internally, the facette for the ptery- 
goid already alluded to. This process is subcompressed from before 
backwards, and has throughout a gentle curvature upwards, having 
much the form of the thorn of the common rose, without its sharp point. 
There are two articular facettes on the inferior side of the mandibular 
end, divided by rather a deep depression. Of the two, the inner is the 
larger and more symmetrical in form, being transversely elliptical. The 
outer one seems to be borne on rather a constricted neck, having on its 
outer aspect the acetabulum for the hemispheroidal facette on the squa- 
mosal. The anterior surface of the body is smooth and triangular in 
outline 5 the opposite and inner surface, somewhat similar in appearance, 
presents for examination, just below the mastoid process, a large, oval, 
pneumatic foramen; other of these openings may exist in the depression 
on the posterior surface of the body of the bone already described. 
The inferior surface of the hasi-sphenoid is convex outward, and slopes 
away gradually into the rostrum, anteriorly. The external orifices of 
the Eustachian tubes are extremely minute, as are the foramina for the 
entrance of the branches of the common carotid to the cranium. As 
already intimated when speaking of the pterygoids, there are no ptera- 
pophysial processes. 
The external aperture to the cavity of the otocrane is an elliptical 
slit, 1.5 millimetres wide at its widest part, looking almost directly for- 
wards, its lower end being the innermost or nearest the median plane. 
The mastoid, however, does not extend so far forwards but that in a 
direct lateral view we may see, through the opening, the funnel-shaped 
internal orifice of the Eustachian tube. The stability of the ear cavity 
is here, as in many birds, highly enhanced by the presence of numerous 
osseous trabecula?, acting as struts and braces to its walls. 
An examination of the interior of the brain-case shows the fossae for 
the several cephalic lobes to be large—indicating a brain of good size 
for the bird. As already defined, the foramina for the first and second 
pairs of nerves are in each case single, and as a whole more or less oval. 
A constriction, however, takes place in their outlines at the middles, 
formed by the encroaching interorbital septum, so that, looking out of 
the cavity, the foramen in either case appears double, whereas a view 
from an orbit reveals the fact of there being but one opening in either 
case. The olfactory foramen is very large—in the dry cranium—the 
deficiency being made up by firm membrane in the living Lark. The 
minute openings for the carotids at the base of the pituitary depression 
are placed, as usual, side by side transversely. The posterior wall of the 
sella turcica is deeply notched. No. 5.] SHUFELDT ON THE OSTEOLOGY OF EREMOPHILA. 
127 
The longitudinal sinus is best seen along the superior and median 
crest, just before it arrives at the olfactory foramen. The middle fossa 
for the accommodation of the cerebellum is distinctly marked by long 
transverse concavities, admitting the rugae upon the lobe in question 
when the brain is in situ. With regard to the structure of this bird’s 
cranium, we may say that it is largely cancellated, the intermaxillary 
and petrosal approaching nearest the compact variety of bone; this fact 
lends to this part of the skeleton a great lightness, and well-prepared 
skulls of this Lark are very pretty objects. 
The most remarkable feature to be observed, however, is the great 
amount of separation between the tables of the vault of the brain cavity, 
being fully a millimetre, and in some localities more, the interspace being 
filled in by quite an open diploic tissue. This condition we well know 
to be a striking feature in the anatomy of the S'frigidcc, but here is a 
bird that has the same arrangement as well marked, we believe, for its 
size, as any Owl in the North American fauna. The outline of the base 
of the cranium in TJremophila approaches the sector of a circle, a figure 
more or less true in all birds, and here, as in most others, the greatest 
departure from that figure being a too great convexity of the subtending 
arc. The length of the radius represented by the middle line is 3.2 centi- 
metres, the intertympanic chord, including the bones, being 1.4 centi- 
metres. We will only mention here, in regard to the free osseous ele- 
ments of the sense capsules, that the sclerotals retain their usual form 
and arrangement, numbering in each eye from thirteen to fifteen. The 
attachment among them is rather firm, remaining as shown in PL IV? 
Pig. 41, after a considerable amount of maceration. The ossicula auditus 
are also present, but a lens of some power is required to study their form 
and arrangement. 
The hyoid arch—(Pi. IY, Pig. 37, seen from below).—This, the haemal 
arch of the parietal vertebra, in no way deviates in this little Lark from 
the usual ornithic characters possessed by it among living birds, in being 
freely suspended beneath the cranium and acted upon by certain mus- 
cles. The glosso- and cerato-hyals seem to be confluent, and the bone 
thus formed consists in two narrow little affairs, that for their anterior 
two-thirds run alongside of each other with a greater or less intimacy, 
to have their tips slightly diverge anteriorly. Posteriorly the ends have 
a still greater amount of divergence, and at the junction of the middle 
and posterior thirds there is a transverse bony bridge, that bears the 
facette for articulation with the basi-hyal behind. Scarcely any antero- 
posterior curvature exists. The posterior tips overhang the articula- 
tion of the thyro-hyals with the confluent basi- and uro-hyal. These 
latter have an expansion to accommodate the articulation referred to, 
bearing on either side small, elliptical, articular surfaces, looking 
backwards and outwards for the heads of the hypo-branchial elements 
of the thyro-hyals. 
The bone is subcompressed from above downwards, the uro-hyal being 128 
BULLETIN UNITED STATES GEOLOGICAL SURVEY. [YoI.YI. 
produced behind by cartilage, or rather tipped by that material, while 
the articulation at the anterior extremity of these confluent bones is 
hidden from view in the superior aspect of the arch by the glosso- and 
cerato-hyals; and, as is common, the inferior lip that thebasi-hyal lends 
to this joint is the longer, and protrudes forward. 
The hypo- and cerato-branchial elements of the thyro-hyals are very 
long, slender, up-curved little bones, produced posteriorly, as the uro- 
hyal, by cartilaginous tips. 
The shaftlets of these delicate elements are slightly flattened from 
above downwards, as are the articular heads. The free extremities have 
a tendency to curve inwards a little, or towards the median plane, as 
well as upwards. 
The lower mandible—(Plate IY, Figs. 22 and 29).—Erernophila is an- 
other example exhibiting the non-approximation of the tomal edges of 
the mandibles in the dry skull, this feature being more often absent 
among Grallatores and many of the Natatores, where these edges come 
in contact with almost an equal amount of exactness as where the bill 
is armed with its horny theca. 
The lower mandible of the Horned Lark seems to be, in point of struct- 
ure, composed almost entirely of compact tissue, and, owing in addition 
to the thorough coalescence of its primary elements, a very firm and 
strong bone. Sutural traces, the indicators of the boundaries of pris- 
tine segments, have entirely disappeared, and no one would ever suspect, 
in examining it, the presence of nine original parts, were he not familiar 
with avian osteology or had the opportunity of dissecting the young. 
The inferior surfaces of the articular ends are on a level with the major 
part of the under rim of the rami, but they are well below the coronoidal 
elevations on either side. They present superiorly the usual undulatory 
surface to meet and articulate with the condyles of the tympanies. 
Below appears a longitudinal ridge, due to the extension upon that side 
of the ramal edges. A knob-like process projects behind, and the true 
articular processes are sharp and rather long. They are directed inwards, 
upwards, and then forwards, having the usual pneumatic foramen above 
and near their pointed extremities. The superior margin of the inferior 
maxilla starts at once from each articular surface, to rise by a moder- 
ate angle to the representative coronoids, a distance of 4 millimetres; 
it then falls gradually to the rounded and anterior termination of the 
bone. It exhibits about its middle, on each side, a long but very low 
convexity, the corresponding shallow concavities being between them 
and the coronoidal elevations. The “coronoids” are marked by deep 
groovelets with raised borders, that extend forwards and downwards as 
far as the interangular vacuity. 
The inferior boundary of the bone, as already stated, rises on each 
side in the inferior articular surfaces, to ascend first for two-thirds of 
its extent on each ramus, then to fall at about an equal angle, to sweep 
round and form the anterior and curved termination in the dentary ele. JVb. 5.] SHUFELDT ON THE OSTEOLOGY OF E REMO PHIL A. 
129 
ment. The median line on the dentary segment averages 5 centimetres, 
this portion of the bone being quite thick and concave above, convex 
below. The general surface, both inside and out, between the bounda- 
ries just defined, is in each case depressed, smooth, and translucent until 
we arrive at the solid dentary portion, where we find it marked by a 
row of minute pits. Of some dozen or more lower maxillae before me, 
one of the most striking differences existing among them seems to be 
the variation in size of the interangular vacuity or foramen. This is 
elliptical in outline with the major axis of the ellipse in the long axis of 
the bone, and in some specimens squarely meet the raised ramal borders 
within, while in other individuals, even though the bone be larger, this 
foramen is markedly smaller. A large concavo-convex sesamoid is found 
between the tympanic and articular end on each side. The long axes of 
these bones are placed vertically, and their concave surfaces look for- 
wards. They are attached to the middle of the pointed articular pro- 
cesses behind by a delicate ligament, and above by the same means; by 
a somewhat broader attachment to the squamosals and tympanies, pos- 
teriorly. 
Spinal column, cervical portion—(Pl. IY, Figs. 22 and 35).—In making 
a study of the vertebral column of this Lark, the student will find 
that he will be materially assisted if he make use of an engraver’s eye- 
lens, or, better still, one of the low-power objectives of a good micro- 
scope, as some of the points for examination are rather minute, and are 
not to be so easily or satisfactorily demonstrated by the unarmed eye. 
The cervical xmrtion of the column is composed of thirteen vertebrae; 
these enjoy, from the atlantal throughout the entire series, a perfectly 
free movement among each other by their several articular surfaces; and 
some form of the sigmoidal curve, characteristic of the bird-neck, is in- 
variably preserved during life and action. We find, too, the majority 
of the salient points pertaining to these segments described by ornithol- 
omists present and strongly marked, and the chief functions of this 
jointed and bony isthmus well carried out—as affording protection for 
the myelon in its passage from the brain to the body below, and the 
vessels from their centre to the brain above. The neural canal, begin- 
ning in the atlas as a transverse ellipse, rapidly becomes circular, re- 
taining this form throughout the tube, only to resume the elliptical again 
in the last two or three segments, where in the thirteenth it seems to be 
of a larger calibre than at the cranial extremity, the ellipse still being 
placed transversely. 
The usual processes of ten of these vertebrae, the third to the twelfth, 
inclusive, afford protection to the vertebral artery and sympathetic 
nerve. By an apparent contraction of the parapophyses in the twelfth, 
the canal is open laterally in this segment. It is confined to the anterior 
third on each side of the vertebrae enumerated, and is exceedingly small 
throughout its extent; its largest calibre being at its commencement, 
its finest in the tenth or eleventh. Among the long vertebrae in the 130 
BULLETIN UNITED STATES GEOLOGICAL SURVEY. [FoI.YL 
middle of the neck the anterior entrance of the vertebral canal are 
ellipses placed vertically. They become more circular as we approach 
the thoracic end of the chain. On the eighth vertebra, mesially, and 
beneath anteriorly, we find, bounded on either side by the parapophysial 
processes, the commencement of the iuterhyapophysial groove or canal 
for the carotid artery. It extends through the fourth vertebra with 
about an equal amount of distinctness and depth. (For names of parts, 
see Explanation of Plates at the end of this paper.) 
It will be seen that the carotid in this Lark is single, and bifurcate at 
a point about opposite the third cervical vertebra, the branches pursuing 
their usual courses above. 
A neural spine is feebly developed upon the axis posteriorly, this 
process becoming more strongly marked on the summits of the next 
three succeeding vertebra), the remainder of the cervical segments being 
devoid of this feature, though we have occasionally found an evident 
attempt at its reproduction in the ultimate cervical. The nethermost 
portion of the pseudo-centrum of the first vertebra has been considered 
to be the atlantal hypapophysis Be this as it may, the hypapophysis 
of the axis certainly has a much greater claim to be termed a process, 
while on the third and fourth segments this spine constitutes one of 
the most marked features of the vertebra, being a longitudinal and quad- 
rate lamina of bone, equally well developed on the two vertebrae in ques- 
tion, directed immediately forward. In the case of the fifth cervical, the 
hypapophysis has again degenerated to a minute median point, to be 
entirely obliterated from the sixth. At the ninth it again makes its 
appearance as a delicate and flattened plate at the anterior margin of 
the vertebra beneath, at the point at which in the carotid canal it is first 
seen in the eighth. In the remaining ones it is prominently developed 
and directed forwards from the median plane in each vertebra as a quad- 
rate lamina. It is usually triplicate in the last, but does not arise from 
a common stem, as in other birds. ' 
Parapophysial processes appear as lateral spines first on the third 
cervical; in the middle of the series they are very long and delicate, 
being parallel with the centrum of the vertebra to which they belong. 
They become markedly suppressed near the termination of this division 
of the spinal column. 
Anterior and posterior zygapophyses retain throughout the cervical 
vertebrae their most common ornithic features; in the middle of the 
neck the postzygapophysial processes are long and bent slightly towards 
the neural canal, leaving quite an extensive lozenge-shaped space be- 
tween them in this region where the cord is unprotected by bone; the 
interarticular facets among the centra likewise retain their most com- 
mon avian characteristics. The bodies for the most part seem to be 
slightly compressed from side to side, with a faint inferior median crest. 
The fourth vertebra has a delicate and outwardly arched interzygapo- 
physial bar, that includes within it an elliptical foramen on each side of No. 5.] SHUFELDT ON THE OSTEOLOGY OF EREMOPHILA. 
131 
some size. This bony connection in the third vertebra nearly fills in the 
interzygapophysial space, a very minute vacuity alone remaining. 
All the cervical vertebrae appear to be pneumatic, but the foramina 
in some of them are excessively small and difficult of detection. 
What could be more exquisite in texture or offer a prettier subject for 
study than the atlas of one of the smaller vertebrates such as our pres- 
ent subject | When we see it analyzed in the minutest details, carried 
beyond its mere gross anatomy, what interest, what wonder we experi- 
ence, and how we marvel still when we realize the significance of this 
bone, with its variously modified autogenous and exogenous parts— 
a vertebra. 
* Here, in the atlas of Eremophila, the bird-head, as far as its bony sup- 
port is concerned, rests in a diminutive cup not half a millimetre wide 
or deep, that may or may not be perforated by the odontoid process of 
the axis; in fact, quite an amount of osseous tissue intervenes, which 
seems to be due to a short odontoidal style in the majority of instances, 
rather than a lengthening of that part of the atlas that receives it. 
A square bony plate projects from below, more anterior than any 
other part of the bone, that covers the atlo-axoid articulation in front. 
The arch that connects the neurapophyses is broad and smooth, 
and assists greatly in the protection of the myelou between the two 
bones. 
The odontoid process on the axis is concave in front, flat behind, with 
a roundish summit. It averages one millimetre in length, and is directed 
slightly backwards. The articular surface at its base is reniform in 
outline, the centrum that supports it being contracted below. The 
postzygapophyses show faint traces of auapophysial tubercles; these 
are better marked in the latter cervicals. The last or thirteenth verte- 
bra has freely suspended from beneath each diapophysial articular sur- 
face a rudimentary pleurapophysis that averages about two millimetres 
in length. These little bones represent the only true cervical ribs, though 
we must admit here that in several individuals we found the first pair 
of dorsal pleurapophyses unconnected with the sternum by the usual 
hsemapophyses, and ending in pointed extremities. Should such a speci- 
men alone be examined, we would have to recognize fourteen cervical 
vertebrae, the last two bearing free pleurapophyses, but the common rule 
must dictate here as elsewhere, and the condition just mentioned be 
reckoned as the exception. 
Dorsal vertebrae, vertebral and sternal ribs, sternum—(Pl. IY, Figs. 22, 
24, 27, and 38).—The number of vertebrae devoted to the dorsal portion 
of the spinal column in Eremophila seems to be invariably Jive. They 
are easily detached one from another, and after ordinary maceration of 
the skeleton drop apart almost as readily as the cervical vertebrae, so 
that during life there is at least quite a little amount of free movement 
among these bones. 
The neural canal, as it passes through this series, starts with the 132 
BULLETIN UNITED STATES GEOLOGICAL SURVEY. [FoLTL 
transverse ellipse as we left it in the last cervical, in the vicinity 
of the dorsal expansion of the myelon, to terminate nearly circular, and 
much diminished in calibre, in the ultimate segment of the sacral ex- 
tremity. 
The neural spines form by their interlocking a continuous ridge above. 
The thickened crest of this ridge is produced by what wre will call the 
arrow-head joint, a true schindylesial articulation to be found in many 
of the class. The superior margin of each spine becomes pointed ante- 
riorly, extends forward, and is received into a fissure of the posteriorly 
produced superior margin of the neural spine of the vertebra next be- 
yond it. This arrangement has the appearance of so many little arrow- 
heads placed in similar juxtaposition, and constitutes one of the elements 
of stability of the dorsal vertebra in this bird. The open spaces remain- 
ing among the bodies of the spines below, between their produced crests 
and the several neural arches, are filled up by connecting ligament and 
membrane. 
The diapophyses of the dorsals are a very much horizontally flattened 
series. They are all slightly tilted upwards, the anterior ones being the 
broadest and shortest, and the ultimate one, by a gradual departure in 
this regard from the first, the narrowest and longest. In the middle of 
the series, moderately well developed and antero-posteriorly produced 
metapophysial ridges are found limiting the diapophyses externally; they 
do not reach from one vertebra to another. The pneumatic foramina at 
the bases of these processes are very minute and scarcely discernible 
by the naked eye. 
The inferior diapophysial facettes for the pleurapophysial tubercula 
are concave-elliptical surfaces, with their major axes parallel to the 
median line. The anterior ones are the more circular. 
The zygapophysial processes, to assist in the intimate proximity of 
these vertebra, are short and thick. The anterior ones look upwards and 
inwards, the reverse being the case with the posterior series, which lat- 
ter develop pointed spines that overlap above, each in its turn, on 
either side, the vertebra next behind, at the base of the common neural 
spine. The longer of these processes are found anteriorly; they gradu- 
ally disappear as we near the sacrum. 
The first dorsal hypapophysis consists of three plates, arising from the 
centrum of the vertebra separately, and arranged as shown in Fig. 38. 
On the second dorsal we find only a single quadrate plate in the median 
plane, directed forwards. It occupies a position at the anterior margin 
of the vertebra, but is produced posteriorly as a low, thin lamina of bone, 
along the remainder of the centrum mesial to the raised and posterior 
margin. The third vertebra takes it up in this form, and it is thus 
passed along the series, constituting a continuous hypapophysial ridge, 
intersected by the expanded anterior and posterior borders of the cen- 
tra. 
The articular surfaces among the bodies retain their xsual characters. No. 5.] SHUFELDT ON THE OSTEOLOGY OF EREMOPHILA. 
133 
They extend into the ridge just described. The centra of the dorsal 
vertebra are somewhat compressed in a slightly increasing degree from 
before backwards; each lateral and anterior margin supplies a nearly 
circular parapophysis for the pleurapophysial capital a, while at points on 
the posterior margins in the same plane we find the major share of the 
notch, which in coaptation of the segments constitutes the subcircular 
foramina for the exit of the dorsal nerves. 
There is a free pleur apophysis for each dorsal vertebra, but the first is 
not always connected with the sternum by a sternal rib, as already de- 
fined ; it sometimes has all the characteristics of a movable cervical rib; 
again, when it connects with the sternum, its luemapophysis articulates 
rather high on the costal border (PI. IV, Fig. 22). It may or may not 
bear an epipleural appendage. 
The vertebral ribs of this Lark articulate, as usual, by tubercula and 
capitula, with the dorsals, meeting par- and di-apophyses in the ordinary 
manner. The necks of the ribs in the middle of the series are the long- 
est, and often we find among the ultimate ones a slight projection be- 
yond the tubercle, that is received in a corresponding notch at the outer 
border of the diapophysis it meets. There is but little difference in the 
width of these flat bones ; perhaps the anterior ones have rather the ad- 
vantage in this respect. Minute apertures, to allow the air to enter their 
bodies, are observed in the usual localities. 
The laterally viewed curve of a dorsal rib is barely sigmoidal; viewed 
from in front it approaches a portion of the curve of an arc of an ellipse. 
A ridge continuous with the neck is carried down the inner aspect of 
each bone, to gradually disappear near its middle. The lower extremities 
of these ribs are slightly enlarged, to afford space for articulation with 
the sternal ribs ; the surface is convex. 
The epipleural appendages of the dorsal pleurapophyses are conflu- 
ent with the posterior edges of the bones, and situated below their mid- 
dles. Occasionally the one in the middle of the series has sufficient 
length to overlap two ribs; in young birds of this species they are much 
shorter, and the best-developed ones show an angle on their inferior 
borders just after leaving the rib, as if they had left that bone with the 
original intention of proceeding downwards and backwards at a gentle 
angle, but suddenly changing mind, proceeded directly upwards and 
backwards at an equal angle; hence the condition alluded to. 
When the first dorsal rib articulates with the haemal spine below by the 
intervention of a sternal rib, this latter bone is quite small and delicate, 
averaging about 3 millimetres in length, and but slightly curved. The 
remaining dorsal hsernapophyses become longer and more curved as we 
follow them backwards. They are all flattened from side to side, their 
lower extremities being abruptly twisted at right angles with their shafts, 
enlarged, and terminating in a flattened articular surface for the costal 
border of the sternum. These articular surfaces are dumb-bell shaped, 
L e., contracted in their middles. The upper ends of these sternal ribs 134 
BULLETIN UNITED STATES GEOLOGICAL SURVEY. [FoI.VL 
are also enlarged and laterally flattened for articulation with the verte- 
bral ribs. These latter enlarged ends are sometimes larger, sometimes 
smaller, than the extremity of the pleurapophysis they meet. 
Through the teachings of philosophical anatomy, we must recognize 
in the avian haemal spine or the bone sternum, developed as it may ber 
the confluent haemal spines; and in it, in its maturity, see one of the 
most interesting bones to contemplate, it being one of the most diversi- 
fied in form in the bird skeleton. Owen styled the type of this bone, as 
found in the Lark now under consideration, “cantorial” (Anat. and 
Phys. of Yert., Yol. III). It is certainly typical of the suborder Oscinesr 
as far as American ornithology is concerned; good examples as testify- 
ing to this I have now before me, in the haemal spines of Turd us mi- 
gratorius, Ampelis garrulus, Mimus polyglottus, Lanius, and many others. 
In Eremophila the sternum is very light and delicate in structure; so 
thin is it in some individuals that we find deficiencies occurring, usually 
in the body, as foramina of no mean size (1.8 millimetres). Its outer 
surface, indeed the entire surface of the bone, has the appearance as if 
it were venated, the solid bony veins being thicker and more opaque 
than the general surface of the bone, and branching from the various 
borders. 
The carina is moderately well developed, measuring in the vertical 
line below the coracoidal groove 9 millimetres. Its inferior border, ex- 
panded behind, is rounded and somewhat thickened; this thickening 
disappears on the anterior border, which is sharper and continuous with 
a conspicuous crest on the front of the manubrium. 
The carinal angle, with an aperture of 70°, is quite prominent and 
produced anteriorly. Just within the anterior margin of the keel we 
find a rather prominent carinal ridge, its lower extremity branching 
backwards, and by its ramifications taking part in the superficial vena- 
tion referred to above. The keel arises abruptly from the inferior and 
median angles formed by the sides of the body where they meet, mesiad. 
The xiphoidal prolongation is profoundly notched once on each side. 
These notches have the outlines of isoceles triangles, with their angles, 
rounded, and apices but a short distance from the costal borders. These 
deep indentations of the xiphoid give rise on either lateral sternal bor- 
der to a long, stout process, extending backwards and outwards, with 
dilated extremity. 
The outer surface of the body of the sternum presents for examination 
well-marked pectoral ridges, and, running from the bases of the xiphoidal 
processes to the outer angles of the coracoidal depression, clearly defined 
subcostal ridges. 
The manubrium is aprominent, superiorly bifurcated, trihedral process,, 
jutting out from a substantial base in the median plane, forwards and 
upwards, from the angle formed by the coracoid groove and the front 
border of the carina. At its base internally there is an extensive oval 
pneumatic foramen. Its bifurcations are rounded, and give attachment A'o. 5.1 SHUFELDT ON THE OSTEOLOGY OF EEEMOPHILA. 
135 
at their extremities to firm ligaments, that pass directly to the coracoidal 
capitula above. 
The groove for the coracoids is markedly impressed and continuous in 
front, extending from costal process to costal process; its boundaries 
form the thickest and stoutest part of the bone we are describing. 
The costal processes, possessed of broad bases, arise as thin but prom- 
inent lamina, upwards, forwards, and outwards, terminated by flattened 
summits. Their posterior margins bear the costal facets for the articu- 
lating ends of the sternal haem apophyses. 
The sides of the body of the sternum on its ventral aspect make an 
obtuse angle with each other. The line of meeting in the mesial plane 
is quite evident; its anterior half is the seat of a row of various-sized 
pneumatic foramina. There are upon each costal border five, sometimes 
six, transverse facettes for the sternal ribs; the shallow depressions among 
them are scantily supplied with pneumatic foramina. 
The mid-xiphoidal border, in which the keel terminates posteriorly, is 
thickened; its other boundaries are sharp, with raised ridges below, 
just within their edges. The greatest length of the sternal body is a 
little more than two centimetres, and its greatest width a little more 
than one centimetre, the last measurement taken to the rear of the cos- 
tal processes. 
Sacral vertebrae and ribs, pelvis, coccygeal vertebrce—(PL IV, Figs. 22, 
23, and 28).—The first sacral vertebra has become thoroughly confluent 
with the ossa innominata on either side and with the vertebra behind 
it. Its diapophyses seem to have spread out upon the under surface of 
the ilia, combining with them, for we observe that the first sacral pleu- 
rapophyses articulate in the ordinary manner with the transverse pro- 
cesses and the parapophyses, the tubercula being situated just near the 
outer iliac borders. This rib may become, as a rare event, confluent 
with the pelvis, but is usually free. Its hmmapophysis is the longest of 
the series, and the articular facette on its lower extremity meets the 
last facette upon the sternal costal border. This sacral pleurapophysis 
may possess an epipleural appendage, though it seems to be the excep- 
tion. 
The second sacral rib is a delicate hair-like bone of uniform thickness, 
that does not show any decided tubercle, merely, after leaving the ver- 
tebra, coming in contact with the under surface of the ilium, on each 
side, for the entire interspace between the tubercle and head. It, too, 
may become confluent with the pelvis on its lower surface. 
Extending downwards and forwards by a gentle curve, it meets its 
hsemapophysis through a miniature articulation. This latter style articu- 
lates along the posterior border of the sternal rib of the first sacral 
pleurapophysis, never reaching the costal border, and the second sacral 
rib never bears an epipleural spine on its posterior border. 
The sacral vertebrae are invariably confluent throughout the chain in 
the pelvis of the Horned Lark; indeed, it is only by a process of staining 136 
BULLETIN UNITED STATES GEOLOGICAL SUEYEY. [VoI.VI. 
this remarkable compound bone, and the aid of a strong light, that they 
can with any satisfaction be counted. There are eleven of them ; excep- 
tionally, twelve. 
The neural canal, circular at the outstart, shows the usual pelvic swell, 
chiefly anterior to the acetabula, conformable with the ventricular dila- 
tation of the myelon in that locality. The exit of this tube distally is 
likewise nearly circular. The foramina along the bodies of the centra, 
in the vicinity of the dilatation referred to, are double and placed one 
above another, for the separate egress of the roots of the pelvic plexus* 
The anterior aspect of the first sacral vertebra presents every element 
and process requisite for articulation with the ultimate dorsal segment. 
It is largely overshadowed by the ossa innorninata. Opposite the iliac 
contraction, in the neighborhood of the fourth and fifth sacrals, these 
vertebrae throw out their par- and di-apophysial processes far enough to 
meet and brace the iliac bones. We do not meet with such braces again 
until arriving opposite the acetabula and beyond, where the parapo- 
physes project upwards and unite with the outer margins of the trans- 
verse processes, the ilia articulating with the free and united borders. 
Foraminal deficiencies not unusually occur among these processes, more 
particularly between the last two sacrals, where they seem to be con- 
stant, though of varying size and shape in different individuals. 
The last sacral vertebra is markedly compressed from above down- 
wards, retaining, however, all the elements required in articulation with 
the first and much-modified coccygeal vertebra. 
Viewing the confluent sacral vertebrae, or the “ sacrum11, from above, 
we find the united neural spines, as a vertical lamina, dividing the ante- 
rior interiliac space into two capacious ilio-neural grooves at that moiety 
of the bone. 
This common neural spine and the ilio-neural grooves proceed back- 
wards until the gluteal ridge of the ilium curves outward to the antitro- 
chanter on either side. At this point the spine disappears with the 
grooves, the sacrum becomes nearly flat and spreads out, to gradually 
contract again before its ultimate dilatation in the diapophyses of the 
last vertebra. 
The ornithotomist will find, in reviewing the skeletons of our avian 
types that the ilio-neural grooves, as seen iu this bird, are very fre- 
quently converted into canals in other orders, by meeting of the inter- 
ested bones above. The condition as defined, however, in the previous 
paragraph, as relating to Eremophila, seems to be characteristic of Amer- 
ican Oscines. The sacrum is slightly convex from before backwards on 
its upper surface, moderately concave along the confluent centra below. 
The pelvis of this bird is uncommonly wide and short, and the ischi- 
adic and pubic posterior extremities remarkably flared outwards. The 
anterior and inner angle of each ilium, apparently assisted by the dia- 
pophysis of the first sacral vertebra from beneath, is pointed 5 the ante- 
rior border slopes backwards gradually, for a distance of 3 or 4 milli- &0. 5.] SHUFELDT ON THE OSTEOLOGY OF EEEMOPHILA. 
137 
metres, to the rounded anterior external angle of the ilium. Between 
this point and the acetabulum the iliac border is markedly concave in- 
wards, as is the surface of the bone above it, the preacetabular being 
included between this border and a well-defined gluteal ridge. The 
superior postacet abular iliac surface is nearly square in outline, convex, 
and equal to a little more than one-third of the bone. It is thin and 
translucent, its outer and posterior borders receiving the greater share 
of osseous reenforcement, particularly in the vicinity of the antitro- 
ehanter. 
Posteriorly, this bone, slightly aided by the ischium, is carried out 
from an ilio-ischiadic, overhanging crest, as bony processes, with their 
points turned slightly inwards. 
These processes are strongly marked in another of our Oscines, Jlar- 
porhynchus rufus, a bird that has a notoriously angular and unique pelvis. 
The antitrochanter is subelliptical in outline, and faces downwards, 
forwards and outwards. The articular surface is produced downwards 
as far as the cotyloid cavity, upwards slightly above the general sur- 
face of the ilium, and is bounded posteriorly by the ischiadic notch. 
The foramen at the base of the truly hemispherical cotyloid cavity 
has so far absorbed the bone that really scarcely anything remains of it 
beyond a cylindraceous acetabular vacuity, the internal and external 
apertures being circles of equal diameter, and the femur consequently 
relying almost exclusively upon its fleshy and ligamentous attachments 
to retain its head in the ring. 
Sutural traces of the margins of the pelvic bones as the components 
of this osseous ring have entirely disappeared, having been obliterated 
during the pelvic consolidation. 
The ischium, for its major part, is like the ilium—very thin, more par- 
ticularly so at its free posterior borders; joining with the ilium behind, 
it shuts off a large and elliptical ischiadic foramen, the superior arc of 
which is situated just beneath the ilio-ischiadic crest described above. 
The major axis of this ellipse is directed downwards and backwards. 
The posterior extremity of the ischium has an odd-appearing, foot-like 
termination, that is bent down to meet the pubis. 
This latter bone is an extremely slender style, that, immediately after 
assisting in the formation of the cotyloid ring, closes in a small, in fact 
the smallest of the group, subcircular obturator foramen behind; then, 
running parallel with the ischium, by touching its further end encloses 
another long spindle-shaped vacuity; it is finally produced beyond that 
bone by a pointed extremity, that curves backwards and inwards. 
It only remains now to say of the pelvis, as far as its internal aspect 
is concerned—after what we have said in regard to its extreme lightness, 
its translucency, its sacrum, and its borders—that, in general, superior 
convexities cause or create internal concavities, and vice versa. It is ca- 
pacious and firmly united; any attempt to remove the ossa inuominata, 
in the adult bird, from the sacral border, invariably results in failure and 
usually longitudinal iliac fracture. 138 
BULLETIN UNITED STATES GEOLOGICAL SURVEY. [VoZ.VI. 
There are seven coccygeal or caudal vertebral, rarely only six, and the 
pygostyle; they are in the skeleton so arranged and articulated that 
they have, as a whole, a gentle curve upwards, terminated by the quad- 
rate “ coccygeal vomer”. 
These segments are all free, being easily individualized, even before 
maceration, by simple section of the ligaments that bind them together. 
The subcircular neural canal, that passes through them, almost capil- 
lary in its dimensions, terminates without passing into the pygostyle. 
There is no haemal canal developed, and indeed hypapophyses are 
found as stunted tubercles only on the last two or three vertebrae. 
A neural spine is developed on each, as a prominent and curved “pro- 
cess” pointing forwards; this spine is wanting, however, on the last 
caudal. 
Of the lateral apophyses the transverse processes seem to be the only 
ones entitled to any consideration; these, as broad, flattened lamina, 
extend from each vertebra, downwards and outwards, decreasing in 
width from before backwards ; in fact, each vertebra in the coccygeal 
series becomes more and more rudimentary as we proceed in that di- 
rection. 
The articular facettes upon the centra start reniform, to terminate 
almost circular in the last vertebra; and the zygapophysial processes 
are exceedingly elementary in character. 
The pygostyle is parallelogramic in outline, articulating with the ulti- 
mate coccygeal vertebra by an imperforated cup-shaped depression, at 
the middle of its long anterior side. The edge of the bone above this 
point rests on the posterior border of the neural spine of the last caudal; 
below it is free. 
The superior angle is more or less produced, and the posterior corner 
of the parallelogram is expanded laterally; this expansion is highly 
developed in many birds, as in Golaptes mexicanus and other members of 
the family Picidce. The caudal vertebrae are non-pneumatic in our pres- 
ent subject, whereas in the pelvis we find these foramina in their usual 
localities. 
The scapular arch—(Pl. IV, Figs. 22, 30, 32, 33, and 34).—This arch 
is very strong and perfect in this bird, as it is among the Oscines gen- 
erally. 
The bones can be easily separated from each other by maceration, 
though during life they are remarkably well strapped together and to 
the sternum by their numerous ligaments. 
The scapula lays along the dorsum in its usual position over the dorsal 
pleurapophyses, parallel with the vertebrae, with its posterior point 
touching the fifth one in the vast majority of the specimens. 
Certain bones in all skeletons force upon us their resemblance to fa- 
miliar objects, and we know many of them have received their distinct- 
ive appellations through such likenesses; more particularly is this the 
case in the skeleton of man, where the bone we are describing is fre- No. 5.] SHUFELDT ON THE OSTEOLOGY OF EREMOPHILA. 
139 
quently termed the shoulder-Zdade, but how much more blade-like is the 
scapula in this Lark and many other birds, as far as shape is concerned. 
It is truly a miniature bony cimeter in Erernophila. This is not true for 
scapulae*of all birds, ho tvover, for no one would ever be struck by such a 
resemblance while regarding the J-shaped scapula of Golaptes mexicanusr 
or the straight, almost square-cut bone in some of our natatorial birds. 
In the Horned Lark the scapula is pointed and obliquely truncate 
behind for more than a third of its slightly dilated posterior portion, on 
the side towards the vertebrae. 
The outer border is reenforced by a rounded ridge for nearly its en- 
tire length, while the inner is quite sharp. 
The blade becomes stouter and subcompressed as we near the gle- 
noidal processj this broad tuberosity extends downwards, forwards, and 
outwards, and is crowned on its entire summit by a curved, subcircular,, 
articular facet, that supplies rather more than one-third of the glenoid 
cavity for the head of the os humeri. 
The acromial process is bifurcated, and the clavicular head rests in the 
fork. The larger bifurcation is the lower, and both rest against the 
coracoid, on the inside and jnst below the head, creating the usual 
scapulo-coracoid foramen, which in this case is not very extensive. 
The scapula is pneumatic, and the foramina are to be found at the ex- 
tremity of the larger bifurcation of the acromial process, and in the notch 
between the two. 
The coracoid can boast of a very fair subcylindrical shaft between its 
head and inferior expansion. This flared extremity is quite thin out- 
wardly, stouter within, where it appears to be more of an extension and 
spreading of the shaft in its course downwards. Below there is a nar- 
row crescentic facet for the sternum, and at the upper edge of the exterior 
and thin side of the dilated end we find a notch, sometimes a foramen,, 
that appears to be constant. 
The upper extremity of the coracoid is an irregular tuberosity, con- 
sisting of a lower, inner, and smaller process for articulation with the 
clavicle, and an upper, superiorly convex head, that curls over mesiad to 
create a fossa, at the base of which we discover a group of various-sized 
pneumatic foramina. Anteriorly the head shows rather a well-marked 
process, into which the ligament coming from the horn of the sternal 
manubrium, of the same side, is inserted. 
To the outer aspect, and below the head, is the reniform and vertical 
facet that, with the scapula and os humero-scapulare, goes to complete 
the glenoid cavity. 
The os humero-scapulare is a free bone, rather larger than the patella, 
found at the upper and posterior angle of the glenoidal process of the 
scapula. It is an elliptical disc, with a peg-like process extending from 
it from behind. The outer surface is concave and articular for the com- 
pletion of the glenoid cavity. This ossicle is held in position by various 
fibrous ligaments stretching from its borders to the scapular arch and 
the humerus. 140 
BULLETIN UNITED STATES GEOLOGICAL SURVEY. [Vol.Yl. 
The clavicles are thoroughly fused together, forming one deeply fi- 
sh aped bone; their cylindrical and curved lengths support at the union, 
mesially and below, a long lamina of bone, in the median plane, that is 
directed upwards and backwards, parallel to the anterior carinal crest, 
to which it is united by ligament in the living bird. Their upper ends 
are expanded and placed in the skeleton flat-wise against the acromial 
process of the scapula and the head and the lower or clavicular process 
of the coracoid. The acromial process, through its bifurcation, partially 
grasps the hind border of this expanded end of the furculum, on either 
side. 
This bone seems to be non-pneumatic, while the coracoids are hollow 
almost throughout their entire extent, having in their composition very 
little cancellous tissue and a thin though firm, compact layer. The scap- 
ulae are hollow for some little distance into their blades, to be terminated 
by a cancellous structure, with an external and attenuated outer compact 
coat. 
With the scapula arch in situ, we observe that the coracoids do not 
meet below in the coracoidal groove of the sternum, but approach only, 
on each side, as far as the periphery of the pneumatic foramen at the 
base and behind the manubrium. 
They are directed upwards, forwards, and outwards, at an angle of 
about 45° with the horizontal plane, the skeleton being erect; and, as a 
consequence, we find their upper ends further apart than any other part 
of the bone. 
The aperture between scapula and coracoid is in nearly a right angle, 
and the straight part of the inner scapular borders are parallel, their 
obliquely cut ends alone slightly turning outwards. 
A scapula is 2.5 centimetres long, a coracoid 3 centimetres, the in- 
terclavicular space above being 1 centimetre. 
In Turdus migratorius, as perhaps the best representative of avian 
structure among the Oscines, we find the scapula shorter in proportion 
when compared with the other bones of the arch; the coracoids more 
depressed, i. e., more in line with the sternum; and the furculum in its 
direction backwards showing a gentler curve. 
The upper extremity—(Pl. IY, Figs. 22, 31, 36, and 43).—The pectoral 
limb in JEJremophila maintains the usual ornithic characters of a great 
number of the class, both in arrangement and number of the bones com- 
prising it. The skeleton arm has ten distinct segments; of these, we 
find one devoted to the brachium, two to the carpus, one to the metacar- 
pus, and four to the phalangeal portion of the manus. 
In ornithotomy we find the head of the os humeri playing in a shallow 
glenoid cavity, composed of the glenoid process of the scapula, the hu- 
meral facet of the coracoid, and here, in addition, the os humero-scap- 
•ulare; the homologue of the humerus’ summus not entering into the 
scapulo-humeral articulation as an overarching and protecting process, 
as we find it in human anatomy. No. 5.] SHUFELDT ON THE OSTEOLOGY OF EREMOPHILA. 
141 
The bone humerus in this bird is more remarkable for its lack of curv- 
ature than anything else, being short and straight, as in others of the 
suborder among which our subject is classed and belongs. 
The head of the bone is broad and moderately flexed anconad, de- 
veloping only a very narrow and thin radial crest, which is bent for its 
entire extent toward the palmar aspect. This crest, answering to the 
“ greater tuberosity ” of anthropotomy, and giving attachment to the 
usual muscles, extends along on a straight line on the upper aspect of the 
shaft longitudinally for only about half a centimetre. 
The ulnar tubercle, or lesser tuberosity, makes up the thickened and 
proximal border of the confines of the pneumatic foramen; a deep little 
pit on its palmar side or margin lodges the extremity of a strong liga- 
ment coming from the head of the coracoid of the same side, and mate- 
rially assists in keeping the head of the humerus in its socket. 
The elliptical and convex articulating facet of the head curls over an- 
conad, and from its middle a line runs down the bone for a short dis- 
tance, being one of the angular boundaries of this the trihedral extrem- 
ity of the bone. Quite a notch exists between the facet just described 
and the wall of the pneumatic foramen. This latter is on the under side 
of the head of the bone, surrounded on its upper, proximal, and lower 
aspects by a firm bony wall, the lower and proximal parts of which are 
continuous with the smooth and otherwise unbroken surface of the ex- 
panded and palmar side of the “head”. 
The pneumatic fossa thus formed is deep, having at its bottom the 
foramen alluded to. Quite often the aperture is multiple, and vast 
differences in size exist, being very large in some individuals, nearly 
consuming the base of the fossa where it is found. From the lower 
boundary of the pneumatic enclosure another longitudinal line is seen 
on the proximal end of the shaft, limiting the anconal face of the trihe- 
dral end of the humerus in this direction. The palmar aspect of the 
head, broad and smooth, arches gradually inwards and towards the 
articular facet; it is also slightly convex from above downwards, 
supposing the bone to be in situ and in its position of rest, as we do 
during the course of our description. 
The shaft of the humerus is subcompressed from within outwards, 
smooth, and, viewing it laterally, it is barely convex above, by virtue of 
the ends being bent slightly down; viewing it from above, we may say 
that it is almost straight. 
It retains its form until close under the expanded distal extremity, 
which is curved palmad. On the radial side of this end of the bone we 
find the transverse and convex elliptical trochlea below, for the sigmoid 
articulating depression of the ulna. This has interiorly the quadrilat- 
eral internal condyle. 
The ulnar convexity is separated from the oblique tubercle for the ra- 
dius most effectually by a deep, well-marked, though narrow, notch. 
The oblique tubercle maintains its usual position as formed on this 
bone in birds generally. 142 
BULLETIN UNITED STATES GEOLOGICAL SURVEY. [ToI.VI. 
The trochlea surface does not extend inwards very far; i. e., does not 
pass over the end of the bone. Above it and towards the proximal end 
appears a distinct and prominent “external condyle”. 
Ancon ad this extremity of the humerus presents for examination the 
ui)turned internal condyle and a longitudinal tendinal groove, situated 
opposite the radial convexity, with intervening indentations. This ar- 
rangement lends to this aspect of the bone rather an uneven and tuber- 
ous look. The nutrient foramen, almost too minute to be observed by 
the naked eye, is found at the middle and inner aspect of the shaft. 
The radius is a long, delicate bone, with a bent and compressed shaft. 
A moderately well-expanded and circular “ head ” presents the usual 
concavity for the oblique tubercle of the humeral trochlea, while below 
is a feebly marked “ ulnar facet ” and bicipital tuberosity; beyond this, 
again, the shaft develops a sharp, protruding edge, that extends nearly 
to mid-shaft and into the interosseous space. 
The distal extremity of this bone is spread transversely and curved 
downwards. It articulates with the upper surface and distal end of the 
ulna, and is lined above by very minute tendinal grooves. The outer 
border of this extremity presents a transverse lamina of bone that seems 
to be superadded to the truly dilated end. 
In articulation, the radius at first curves away from its companion, 
the ulna, to approach it again towards the carpal end, for about the outer 
third of the shaft, to remain with it until both arrive at the wrist. The 
distal border of the radius is transversely convex for an articular facette 
on the scapho-lunar. The ulna is the main bony support of the forearm, 
and, indeed, its shaft is nearly equal in size and strength to that of the 
humerus itself, having the appearance of being the true continuation of 
the pectoral limb, so diminutive and slender is the accompanying radius. 
Its proximal extremity is the larger, and is gently curved anconad, 
to rndet the corresponding flexure of the brachium to form the elbow- 
joint, the articular surface engaged being quite extensive and vertically 
expanded. The lower, circular, and markedly concave trochlea is the 
greater sigmoid cavity, and is intended for the ulnar tubercle of the 
humerus. Its proximal margin is so produced as to form a strongly 
defined “olecranon process”, the lower lip of the cavity being thehomo- 
logue of the “coronoid process”, and is so feebly developed as to scarcely 
deserve the distinction. In close proximity to the greater sigmoid cav- 
ity, above, there is another articular surface, quadrilateral in outline, 
decidedly concave from above downwards, much more shallow in the 
opposite direction, for the oblique tubercle. Immediately beyond its 
distal margin is a weak and shallow facette for the side of the head of 
the radius, so that the oblique tubercle articulates in a cavity furnished 
by the cupped-head of the radius and the larger quadrilateral trochlea 
of the cubitus, the two being almost continuous. 
The outer aspect of this extremity presents simply certain feeble ele- 
vations and depressions for muscles and the ligaments surrounding the 
joint. No. 5.J SHUFELDT ON THE OSTEOLOGY OF EREMOPHILA. 
143 
From the proximal extremity the nearly cylindrical shaft curves 
gently palmad from its inner third only ; after that it takes a compara- 
tively straight course for the wrist. The anconal aspect of the shaft 
presents at the junction of the inner and middle thirds an elliptical nu- 
trient foramen, that enters the bone almost perpendicularly to its long 
axis. The tubercles for the iusertion of the bases of the quills of the 
secondaries, so prominent on this bone in some birds, as in Colaptes, 
seem to be entirely absent. We find them barely present in Harporhyn- 
chus, quite strongly marked in Lanius. The carpal extremity of the 
ulna is likewise articular, being vertically cleft and curved downwards. 
Anconad it develops a rough eminence, and above a depression for the 
fan-like expansion of the radius. This end, as in the majority of the 
class, articulates with the three carpal bones and the radius above. 
The humerus measures 2.4 centimetres, the ulna 3 centimetres, and the 
radius 2.7 centimetres j but the bones in situ and the wing closed, the 
anti-brachium projects beyond the brachium about 5 millimetres. The 
bones of the forearm, though hollow, are apparently nonqmeumatic, as 
is the case with the carpals and long bones of the manus. 
As in the great majority of the class, the bird-wrist is composed of 
the two free carpals and the os magnum, which is confluent with the 
proximal extremity of the second metacarpal. 
The superior and smaller carpal is the scaphoid, here an irregularly 
shaped bonelet, introduced among the cubitus, the radius, and the conflu- 
ent os magnum, with a distal articular face for the latter and two proximal 
ones for the trochlese of the anti-brachium. Between the scaphoid and the 
cuneiform, the other free and inferior carpal, there exists an interspace, 
where the ulna meets the os magnum. 
The cuneiform has an elongated facet on its outer aspect for the ulna, 
and two articular processes that grasp the metacarpal below—an arrange- 
ment that admirably meets the action required of the avian wrist. 
The last carpal merely constitutes the trochlear head of the confluent 
metacarpals; by a gentle and backward sweep its general surface is 
directed inwards. 
The composition of the metacarpal bone of this bird does not deviate 
from the general rule, as applied to the class, in any important particu- 
lar. The three long bones comprising it are firmly anchylosed together 
and bear the fingers. The shortest and first metacarpal, obliquely fused 
with the anterior and upper end of the second, supports a free and pointed 
index digit. The second, or “medius”, supports, first in order below, a 
phalanx peculiar to birds, that is at once recognized by its expanded 
posterior border. It is here deeply concave on its inner surface, which 
concavity is partially divided by a feeble transverse line. 
The “ blade ” of this bone is quite thin in some birds, though the gen- 
eral surface is absorbed, leaving nothing but the rounded and limital 
borders, as in Larus delawarensis and others. 
The neck of this bone is but moderately constricted between the blade 144 
BULLETIN UNITED STA'i'ES GEOLOGICAL SURVEY. [YoI.YI. 
and articular facet for tlie metacarpal to which it belongs. It bears be- 
low another, and the smallest, phalanx of the hand, a little, free, sharp- 
pointed finger, markedly compressed, that completes the skeletal bird- 
arm distally, it being the ultimate segment. 
The third metacarpal, termed annularis, a slender, ribbon-like bone, 
fast above and below to medius, and extending slightly beyond it, also 
articulates distally with another free phalanx, of the general character 
as the index digib and the ultimate joint of the mid-metacarpal, although 
it is longer than either of them. Measuring along the anterior aspect, 
from the summit of mid-metacarpal to the point of its last phalanx, we 
find the man us in Eremophila to average 2.6 centimetres. 
This, the pectoral limb, as we have endeavored to picture it in this 
Lark, with its brachium, anti-brachium, and pinion in proportionate 
equipoise as to length of segments, with its various bones smooth, 
markedly straight, and devoid of those evidences of being acted upon 
by powerful muscles, would require but a single glance from the student 
of avian skeletology to pronounce it as belonging to a bird possessed 
of a flight barely mediocral in rapidity and power. 
Of the pelvic limb—(Pl. IY, Figs. 22, 39, 40,42, 44, and 46).—The inner 
aspect of the upper extremity of the femur presents the usual globular 
head for articulation with the cotyloid ring of the pelvis. It is nearly 
sessile with the shaft, the neck amounting to almost nil. A shallow and 
inconspicuous excavation occurs on the head for the insertion of the 
ligamentum teres. The articular surface that originates with this hem- 
ispherical protuberance extends outwards over the summit of the bone, 
constantly spreading, until limited by the trochauterian ridge, in a 
plane with the outer aspect of the shaft; it occupies a slightly higher 
level than the head, and it is opposed to the anti-trochanter in the articu- 
lated skeleton. 
Anteriorly the trochanterian ridge and line are quite prominent, ex- 
tending a short distance down the shaft, to be lost on the general surface; 
posteriorly it projects outwards horizontally from the articular surface, 
over a shallow concavity that is found immediately below, that presents 
at its base a circular foramen that leads to the hollow shaft, and is 
probably pneumatic, though the femur of this bird does not have the 
appearance of a bone possessed of pneumaticity; the orifice, if nutrient, 
is certainly situated in an unusual place, though we must confess that a 
careful search over the entire shaft with a powerful lens failed to reveal 
any other opening. The trochanter minor is not represented. 
The shaft, for the greater part of its extent, is cylindrical, with a clean 
superficies, undivided by any intermuscular ridges or lines, or, if so, 
very faintly, and decidedly convex forwards. 
The distal extremity of the femur enters largely into the knee-joint, and 
is more bulky than the proximal extremity of the bone. It is directed 
backwards, and, as usual, is divided by an antero-posterior shallow in- 
tercondyloid notch, which is continued up the shaft anteriorly, as the A 0.5.] shufeldt on the osteology of eremophila. 
145 
“rotular channel,” soon to disappear into internal and external condyles. 
The larger and lower external condyle is longitudinally cleft posteriorly, 
so as to afford an additional and outer condyloid surface for the head of 
the fibula, with which it articulates. 
A tuberosity is found behind, just above this cleft, and a few others, 
less prominent and situated more internally, are seen on this aspect of 
the bone, in the popliteal fossa. 
The limiting margin of the internal condyle is sharp and distinct. 
The ordinary features, as tuberosities and muscular lines and markings, 
usually sought for at this end of the bone in nearly all birds, are very 
feebly reproduced in our present subject. 
The proximal extremity of the tibia has a very interesting form, due 
to the prominence of the cnemial ridges. These are attached to the head 
of the bone, well above the horizontal articular surface for the condyles of 
the femur. Their superior border is continuous and convex upwards; 
their inferior borders meet the shaft abruptly, and there terminate. 
Both of these wing-like processes are turned towards the fibular side of 
the bone, the procnemial process being the larger in every respect; and 
the ectocnemial sometimes is produced downwards into a very sharp 
and needle-like spine, a characteristic of other Oscines. They include 
between them a triangular concave and rather deep recess. The expan- 
sion supporting the superior articular surface projects over the shaft of 
the bone in all directions, being quadrilateral in outline, and having an 
articular facet for the fibula on -the outer side, while in the middle 
of the surface, above, a tuberous spine of the tibia exists, with concavi- 
ties on either side for the condyles of the thigh-bone. 
The shaft is remarkably straight, light, and hollow, though apparently 
non-pneumatic, no apertures having been discovered to allow the air 
access to the interior. 
A fibular ridge, 4 millimetres long and 1 millimetre deep, is developed 
in the upper third of the shaft, perpendicular to its outer aspect, for the 
lower articulation of that bone. 
Huxley and Gengenbauer maintain that the distal extremity of the 
tibia represents the astragalus among the Glass Aves, and there certainly 
seems to be some foundation for this assertion, for if we examine this 
bone in the young of any of the Gallince, as in Centrocercus, we find the 
segment that eventually ossifies with this end of the tibia to be rather 
too extensive for a mere epiphysis, and may represent that tarsal bone. 
Without further remark, then, upon this important and still unsettled 
question here, we will observe that in Eremophila, and in all birds, the 
leg-bone terminates distally by two anteriorly placed condyles, separated 
by a well-defined intercondyloid notch. These condyles, approaching 
each other behind, diverging in front, are reniform in outline and shape, 
with their convex surfaces downwards. They are higher on the shaft an- 
teriorly, and the articular portion is more extensive. Likewise, anteriorly 
the shaft is grooved below, to be bridged over just above the “ notch” by 146 
BULLETIN UNITED STATES GEOLOGICAL SURVEY. fYoJ.YI. 
a narrow bony span, arched outwardly, that holds the tendons of the deep 
extensors in position. 
The inner end of this arch is the higher on the bone, and just above 
it, on the shaft, we find a minute tubercle, that gives attachment to a lig- 
ament that is extended to another tubercle lower down on the shaft, and 
on the opposite side. 
The fibula is the merest apology for a bone, represented only by a 
slender spine on the outer side of the tibia. It has a superior and knob- 
like head, that articulates with the horizontally expanded head of its 
sizable companion; lower down it meets the fibular ridge, and is firmly 
attached to it by a strong, fibrous, and close-fitting connection. 
Below the ridge the fibula is continued, hair-like in dimensions, to meet 
the tibia below the middle of its shaft, to become thoroughly and indis- 
tinguishably confluent with it. 
The patella (PI. IY, Pig. 22) is a free bone, and is found in the ten- 
don of the quadriceps extensor. It is compressed antero-posteriorly, 
with an elliptical base above. 
From the points representing the vertices of the major axis of this 
ellipse, bounding lines pass, to meet broadly concave below. The ante- 
rior surface, limited by these boundaries, is convex outwards; the pos- 
terior surface, slightly concave, is divided by a vertical ridge into two 
unequal parts, the outer of which is the greater. The femur averages 
2 centimetres in length, the tibia 3.2 centimetres, and the bone now to 
be described as the tarso-metatarsus nearly 2.3 centimetres, falling be- 
tween the thigh and leg-bone. 
The metatarsals of the second, third, and fourth toes, and certain tar- 
sals at the upper extremity of the bone, coalescing, form the segment, 
tarso-metatarsus, next in order below the tibia, with which it articulates. 
The articular surface of its summit is so arranged as to accommodate 
itself to the condyles of the tibia, consisting essentially of an inner and 
outer antero-posterior facet, and a prominent spine on the anterior mar- 
gin, that accurately fits in the intercondyloid notch of the bone above. 
On the posterior aspect of the bone above we find the u calcaneal n 
process, here approaching a right parallelepiped in form, being vertically 
pierced by four minute cylindrical canals, two next the shaft and two 
parallel with them and above. They are for flexor tendons, which pass 
through them. The shaft is straight, subcylindrical, and hollow, ex- 
panding below for the trochlese for the phalanges. For its upper half 
and posteriorly, ranging below the calcaneal process, it develops a sharp 
vertical crest, that gradually subsides below. * 
The anterior aspect of the shaft is faintly grooved longitudinally, 
and where it dies out below, just above the notch between the third and 
fourth terminal trochlese, we observe a minute perforating foramen for 
the anterior tibial artery. Upon the inner margin of the shaft below 
there is the well-marked though shallow facet for the os metatarsale acces- 
sorium. This diminutive bone is, as usual, slung to the tarso-metatar- Xo. 5.J SHUFELDT ON THE OSTEOLOGY OF EREMOPHILA. 
147 
sus by a ligament, articulating beyond with the hallux. It represents the 
first metatarsal, and has all the appearances of one of the larger-sized 
phalangeal segments, divided obliquely through the shaft, with the cut 
surface closed in and forming the articular surface for the tarso-meta- 
tarsus. Its position, in situ, is figured in PI. IY, Pig. 44. The lower and 
expanded end of the tarso-metatarsus, bearing the trochleae of the re- 
maining phalanges, is further conspicuous for the marked manner in 
which the bone is compressed antero-posteriorly, causing the trochlear 
ends to be placed side by side, transversely. The middle one is the 
larger and grooved entirely round, the one for the second toe being 
slightly the higher and bent a little outwards; finally, the fourth is the 
smallest. Slit-like spaces among these “ processes ” completely divide 
them. 
The joints of the toes are arranged upon the most common plan, and, 
we believe, upon the general rule for all Oscines; i. e., the hallux pos- 
sesses two phalanges, second toe three, third toe four, and the outer and 
last toe five. 
These joints are not impressed with any thing particularly remarkable, 
beyond what is found in them among the class generally. Their verti- 
cally cleft and anterior extremities articulate with the joint beyond, 
which is diminished in size and articulates in like manner with the next 
anterior segment. 
The claws are grooved laterally, and show a process at their proximal 
and lower aspects. 
A glance at PI.IY, Pig. 22, will be sufficient to satisfy ourselves that 
the great length of the claw of the hind toe sometimes seen in Eremo- 
phila, and always characteristic, is due almost entirely to the growth of 
the horny theca that encases it, and not to the length of the osseous 
claw. 
In the figure just referred to, the hallux, with the first metatarsal, has 
been drawn backwards in the skeleton, not only to show the os meta- 
tarsale accessorium, but also a sesamoid, of no mean size, that is found 
on its outer side, an ossicle that betrays its possessor and declares the 
habit he has of spending a good share of his time upon the ground. PLATE 111. 
Various bones of the skeleton. 
Fig. 7. Anterior view of skull, the lower mandible having been removed. 
Fig. 8. H, humerus; i, ulnar tubercle; i', oblique tubercle for radius and ulna; 
h, radial crest; S A and S' A', scapular arch; S and S', scapula; C and C, clavicle; 
Cr and Cr', coracoid ; /, perforating foramen. 
Fig. 9. H‘, humerus; h", radial crest; p/, pneumatic foramina; SA" and S A'", 
scapular arch; S" and S'", scapula; C" and C", clavicle; Cr" and Cr"', coracoid; 
/', perforating foramen. 
Fig. 10. HA, hyoid arch; a, superior view of atlas; a', the same viewed laterally; 
b, the axis; o, its odontoid process. 
Fig. 11. Eight carpus of Bubo virginianus, outer aspect, with the bones composing 
it moved partly from their normal positions to show articulating surfaces; rd, radius; 
ul, ulna; s, scaphoid; c, cuneiform; m, metacarpus; d, index digit. 
Fig. 12. Eight radius and ulna, Speotyto, inner aspect; u, ulna; r, radius; y, artic- 
ular facet for oblique tubercle of humerus, y' for ulnar tubercle of humerus. 
Fig. 13. The same bones, inferior surface, when in position and the wing closed: 
r', radius; u', ulna. 
Fig. 14. Posterior surface, right metacarpus. The differences in form and position 
of such portion of the articular surface in the metacarpus as is shown by z and z‘, in 
Figs. 11 and 14, between Bubo and Speotyto, are here seen; flat and rounded below in 
the first, prominent and pointed in the second. 
Fig. 15. Anterior surfaces, right tibia and fibula; F, fibula; T, tibia. 
Fig. 16. Posterior surfaces, same bones; F, fibula; T', tibia. 
Fig. 17. Eight femur; v, posterior surface; v', anterior surface. 
Fig. 18. Anterior surface, right tarso-metatarsus; m, bony bridge over tendons; j, 
foramen for anterior tibial artery; e, facet for outer toe, I, for middle, and I: for inner toe. 
Fig. 19. Posterior surface same bone; j', the foramen for the anterior tibial artery ; 
e" facet for outer toe, I" for middle, and t" for inner toe; Ic, facet for os metatarsale 
accessorium. 
Fig. 20. A, right os metatarsale accessorium, superior surface; B, base or in- 
ferior surface of right tarso-metatarsus; e‘, facet for outer toe, i, for middle, and t' for 
inner toe. The section of the shaft shows just above the middle facet, on the 
posterior aspect, ranging near the middle third of the bone. BULL U S GE.OL. SURV. VOL. V!. 
PLATE 111 
Fig.^ 
Fl§. 9 
iLI 
Fi4 12 
Fi£, 13 
FitS 
14 
Fife. 12 
Fi§. lb 
Fi§ V 7 
Fife 1c 
FitS 19 
5i^.20. 
TKdf Sinclair•& Son. Lith 
OSTEOLOGY OF SPEOTYTO CUNICULARIA var HYPOG/EA. PLATE IY.* 
Fig. 22. Skeleton of Eremophila alpestris. 
Fig. 23. Sacrum and pelvis from above. 
Fig. 24. The sternum from below. 
Fig. 25. The skull from above. 
Fig. 26. The skull from below. 
Fig. 27. The sternum from above. 
Fig. 28. Sacrum and pelvis from below. 
Fig. 29. Lower mandible from above. 
Fig. 30. The clavicular furculum from in front. 
Fig. 31. Left humerus, anconal aspect. 
Fig. 32. Left scapula and coracoid, internal aspect. 
Fig. 33. Scapular extremity of clavicle. 
Fig. 34. Left scapula and coracoid, external aspect, showing extent of glenoid 
cavity. 
Fig. 35. The thirteenth cervical vertebra, showing first pair of free pleurapophyses. 
Fig. 36. Left humerus, palmar aspect. 
Fig. 37. Hyoid arch from below. 
Fig. 38. Anterior view of sternum, first dorsal vertebra, with its movable pleurapo- 
physes and hsemapophyses, in situ. 
Fig. 39. Right tarso-metatarsus, anterior aspect. 
Fig. 40. Right femur, anterior aspect. 
Fig. 41. Sclerotals, right eye. 
Fig. 42. Right tibia and fibula, anterior aspect. 
Fig. 43. Right ulna, anconal aspect. 
Fig. 44. Right foot, with a portion of the podotheca removed to show the os meta- 
tarsale accessorium, in situ. 
* The figures on this plate are numbered in continuation with the author’s plates and figures to his 
Memoir on the Osteology of Speotyto cunieularia hypogcea. BULL. U.S. GLOL.'SURV. VOL. VI 
PLATE IV. 
Fig 24 
Fig. Er. 
Fig. 25, 
Fig M 
Fig- 41. 
Fig 29 
Fig. 23. 
Fig,33. 
Fig. 22". 
Fig.£B 
Fig 32. 
Fig. 34. 
F^;3s, 
Fig.3B 
Fig SO 
Fig. 37. 
Fig*4o. 
Fig. 46. 
Fig 42 
Fig. 39. 
Fig. 43. 
21 --' 44. 
Fig 31 
Fig 36. 
OSTEOLOGY OF EREMOPHILA ALPESTRIS.