1894. 
NATURAL SCIENCES OF PHILADELPHIA. 
225 
A NEW SUBFAMILY OF MURINE RODENTS—THE NEOTOMINJE—WITH 
DESCRIPTION OF A NEW GENUS AND SPECIES AND A SYNOPSIS 
OF THE KNOWN FORMS. 
BY DR. C. HART MEItRIADf. 
A study of the rich collections of American Murine Rodents 
brought together by the U. S. Department of Agriculture, shows 
that the genus Neotoma is one of a group of closely allied forms 
which differ so radically from the tuberculate crowned Murines, with 
which they have been commonly associated, that the propriety of 
separating them as an independent subfamily seems evident. 
The unparalleled series of Mexican Rodents collected by Mr. E. 
W. Nelson in connection with his work for the Division of Ornith- 
ology and Mammalogy of the U. S. Department of Agriculture, 
contains a large number of wood rats, several of which are not 
properly referable to the genus Neotoma. Two of these were de- 
scribed by me sometime ago, under the names Xenomys nelsoni and 
Neotoma alleni,’ the former being made the type of a new genus. 
In the original account of Neotoma alleni attention was called to the 
circumstance that the crown of the last lower molar is shaped like 
the letter S, instead of exhibiting two transverse loops as usual in 
the genus Neotoma, and it was remarked that this peculiarity might 
prove worthy of subgeneric recognition (p. 1(57). In the course of 
a subsequent study of the American wood rats, it was discovered that 
the character in question, which is one of great value, is correlated 
with a number of important cranial characters, making it obviously 
undesirable to retain the animal longer in the genus Neotoma. 
Ameghino has described and figured two related rodents from the 
Pampean Pliocene deposits near Villa de Lujan, in the province 
of Buenos Ayres, which he has named Ptyssophorus elegans2 and 
Tretomys atavw.3 His description of the former is based on the 
broken ramus of the mandible of an apparently immature iiidi- 
1 Proc. Biological Soc. of Washington, VII, Sept. 1892, 15i>—1H3 ; 167-169. 
2 Mam mi fonts Fosiles <le la Republica Argentina, por Florentine Ameghino 
1889, 111, 112, and pi. iv, tigs. 1, 1 c. 
:l Ibid., lit), 120, and pi. iv, tig. 16. 
September 24,189-4 226 
PKOCEED1NGS OF THE ACADEMY OK 
[1894. 
vidual; that of the hitter is based on a fragment of the maxillary 
containing the upper molar series. At first, I was inclined to regard 
Ameghino’s specimens of Ityssophortts (fig. lc) and Tretomys (fig. 2) 
as the lower and upper jaws of the same animal, and to look upon 
my ‘Neotoma’ alieni (fig. \e) as congeneric therewith.4 Hut sub- 
sequent study has convinced me that Ptyssophorus and Tretomys are 
probably distinct, though closely related genera, and that the living 
species formerly described as N. alleni, together with the new species 
here named vetulus, represent a third genus of the same group. For 
this genus I propose the name Hodomys. Hodomys is a more recent 
type than Ptyssophorus, less specialized than Xenomys, and more 
ancient than Neotoma. 
So far as dental characters go, the group of genera under con- 
sideration (Ptyssophorus, Tretomys, Hodomys, Xenomys, and Neotoma) 
presents nearly every important step in the evolution of the modern 
genus Neotoma from the Cricetine series. Sigmodon seems to be the 
connecting link that bridges the gap between the tuberculate toothed 
Murine subfamily Cricetinse and the tlat topped prismatic crowned 
Neotomime, by which name it seems proper to designate the new 
subfamily, comprising the 5 genera above enumerated.3 Sigmodon 
should be looked upon as an ancestral rather than a contemporary 
type. It is almost on the dividing line between the tuberculate and 
flat crowned groups, and is probably on or near the trunk line 
along which the Neotomime branched off’from the tuberculate series. 
It is evidently an ancient type, dating back to the Pliocene at least,3 
since which period it has not undergone very marked changes. In 
early life Sigmodon has the outer ends of the loops elevated, forming 
half tuberculate grinders, much as in the American ( ricetines, but 
the projecting loops are soon worn down, leaving Hat grinding sur- 
faces (fig. Id). The loops, however, remain closely oppressed or 
even soldered together, never standing out freely as in Neotoma and 
Arvicola. 
4 While of this mind I stated, in a recent paper on the genus Neotoma, that 
the species of Wood Rats having the crown of the last lower molar shaped like 
the letter S, were transferred to the genus Ptyssophorus of Ameghino (Proc. 
Biol. Soe. Wash., IX, July 2, 1894, 117. 
5 It is probable that several other animals described by Ameghino belong to 
the Neotomime—such as Bothriomys and some of the species referred to the 
genera Oxymicterus, Holochilus, and ‘ Habhrotrix' ( Abrothrix). 
K Ameghino has figured an undoubted Sigmodon from the Pampean Pliocene 
(Mamif. Fos. Argentines, pi. 4. fig. 11a). and has referred the same to Holochilus 
vuipinus Licht- 1894.] 
NATURAL SCIENCES OF PHILADELPHIA. 
227 
w hatever the future may show the exact genetic interrelations of 
these animals to be, it is evident that Ptyssophorus is the more primi- 
tive type; Tretomys and Hodomys seem to represent more advanced 
stages in the evolution of the group, while Xenomys and Neotoma 
are more specialized. Xenomys retains more primitive characters 
than Neotoma, and consequently must be looked upon as nearer 
Tretomys, with which it agrees closely in dental characters; on the 
other hand, it is a far more specialized type than Neotoma and can in 
nowise be regarded as holding a place in the direct line of descent 
between Ptyssophorus and Neotoma. 
The discovery of complete skulls of Ptyssophorus and Tretomys may 
show that the line of generic separation should be drawn between 
Ptyssophorus, on the one hand, and Tretomys and Xenomys on the 
other; and believers in comprehensive genera may unite the two 
latter as subgenera of a single genus, the relation of which to 
Neotoma would be that of a specialized ancestral type to a modern- 
ized type. 
The fact that of the living genera only a single species of Xenomys 
and two of Hodomys have been discovered, while nearly thirty species 
of Neotoma are known, is strong evidence that Hodomys and Xenomys 
are survivors of the past, bridging over the gap between Ptyssophorus 
and Neotoma, and that the latter genus is now at or near the height 
of its development. 
Irrespective of the interrelations of these animals, it is evident 
that, collectively, they form an important though not highly special- 
ized subdivision of the Murine series, standing somewhat apart from 
the others. While they resemble the Arvicolime in some respects, 
they differ in numerous important characters and cannot be regarded 
as intermediate between the Arvicolime and ('ricetime. On the con- 
trary, the Neotomime and Arvicolime seem to be independent offshoots 
from the half-tuberculate crowned Cricetines. Among the many ex- 
cellent characters that serve to distinguish these two groups, the fol- 
lowing are sufficient for present purposes:— 
Cranium abruptly and strongly constricted immediately in front 
of brain case, which is quadrangular, projecting squarely into 
orbit; orbital and temporal fossa; well differentiated; jugal forming 
half, or more than half, of outer side of zygoma and always reach- 
Subfamily ARVICOLIN^E. 228 
PROCEEDINGS OF THE ACADEMY OF 
[1894. 
ing forward more than half way from squamosal root to maxillary 
plate; sagittal area subquadrate, usually broader than long; angular 
process of mandible narrow, everted, hamular, and thickened at end; 
infracoudylar notch low and deep. 
Subfamily NEOTOMIN^l. 
Cranium not abruptly constricted in front of brain case, which is 
oval, gradually narrowing into orbit; orbital and temporal fossa* 
indistinguishable, without trace of separation ; jugal wholly poste- 
rior, forming insignificant part of zygoma and never reaching for- 
ward half-way from squamosal root to maxillary plate ; sagittal 
area elongated, at least twice as long as broad; angular process of 
mandible broadly expanded vertically, inflected, not hanmlar, and 
never thickened at end; infra-condylar notch high and shallow. 
The dental characters of the Neotomime may be defined as fol- 
lows: Molars prismatic, rooted or semi-rooted; the crowns flat, 
their sides continuously invested with enamel which is folded on 
itself in such manner as to present on each side of the tooth a series 
of salient loops, alternating with re-entrant angles or interspaces 
(figs. 1-5). M 1, 2, and 3, each with three salient loops and two 
re-entrant angles on outer side; m 1 with three salient loops and 
two re-entrant angles on inner side;7 m 2 and 3 each with two salient 
loops and one re-entrant angle on inner side ; m 1 with three salient 
loops and two re-entrant angles on outer side and four salient loops 
and three re-entrant angles on inner side , with or without an ante- 
rior lobe; m 2 (normally) with three salient and two re-entrant 
angles on each side [Ptyssophorm resembles Siymodon in having 
the antero-external re-entrant angle small]; m a variable, but 
normally with two salient and one re-entrant angles on each side. 
The subfamily Neotomime comprises the genera Neotoma, Xenomys, 
Hodomys, Tretomys, and Ptyssophorm (and probably one or two 
others). 
The Neotomime may be distinguished from the Sigmodont ( 'rice- 
tines by the following characters:— 
Molar crowns prismatic; loops distant; enamel folds of equal 
thickness; crowns flat; antorbital vacuities without spine; palate 
excavated between posterior molars Subfamily Neotomime. 
7 In Neotoma desertorum and arizonce the antcro-iuternal loop is short and 
shallow and becomes obsolete with wear (fig. 5a). 1894.] 
NATURAL SCIENCES OF PHILADELPHIA. 
229 
Molar crowns not prismatic; loops closely appressed; enamel 
folds of unequal thickness, and rising at the free ends to form half 
tubercles; antorbital vacuities with a blunt spine projecting forward 
from top of outer side; palate not excavated between posterior 
molars Sigmodon (fig. Id), Scapteromys, Holochilus(?), and 
other genera. 
In order to render the present account of these highly interesting 
rodents as complete and useful as possible, the genera Ptyssophorus 
and Tretomys are redefined, the new and closely allied genus 
Hodomys is characterized (with reference to the more specialized 
genera Xenomys and Neotoma), and descriptions of all the known 
species are added. 
Genus PTYSSOPHORUS Ameghino [Fossil |. 
Plyssophorus Ameghino, Mamiferos Fosiles Republica Argentina, 1889, 111, 112, 
and pi. iv, figs. 1-lr. Type Ptyssophorus clegans Amegh., from the Argentine 
Republic. 
(Fig. 1, a, b, and c.) 
Crown of m shaped like the letter S placed lengthwise of jaw; 
projecting part of lower incisor nearly straight, slender, and forming 
Fig. 1. a, b, c. Ptyssophorus elegans (from Ameghino). 
a. Eight ramus of mandible, outer side. 
b. Same, inner side (enlarged). 
c. Crowns of right lower molars (enlarged). 
d. Sigmodon hispidus, crowns of right lower molars. 
e. Hodomys alleni, crowns of right lower molars. 230 
PROCEEDINGS OF THE ACADEMY OF 
[1894. 
with its fellow a single sharp, almost spear-shaped, point for piercing; 
symphysis of mandible long, straight or nearly straight, and usually 
bent up at a sharp angle with ramus; the two posterior enamel folds 
of m 1 and 2 simple, reaching completely across the tooth from side 
to side as in m ; each re-entrant angle corresponding to a salient 
loop on opposite side; investing enamel walls parallel, the included 
dentine forming a continuous narrow hand of equal breadth through- 
out. 
Ptyssophorus and Hodomys agree in the following characters :— 
Crown of m shaped like the letterS placed lengthwise of jaw; 
projecting part of lower incisor nearly straight, slender, and forming 
with its fellow a single sharp almost spear-shaped j>oint for piercing; 
symphysis of mandible long, straight or nearly straight, and usually 
bent up at sharp angle with ramus. 
Ptyssophorus and Hodomys differ in the following characters:— 
Genus PTYSSOPHORUS Ameghino. 
(Fig. lc.) 
The two posterior enamel folds 
of m i and m 2 simple, reach- 
ing completely across the tooth 
from side to side as in m ; each 
re-entrant angle corresponding to 
a salient loop on opposite side; 
investing enamel walls parallel, 
the included dentine forming a 
continuous narrow hand of equal 
breadth throughout. 
Genus HODOMYS nob. 
(Fig. \e.) 
All enamel folds of m j and 
m 2 reaching only about half- 
way across tooth; each re-entrant 
angle corresponding (at least in 
young) to re-entrant angle of 
opposite side ; investing enamel 
walls alternately divaricating and 
approximating, the included den- 
tine broken into disconnected 
parts. 
The principal differences between the lower molars of IHyxsophorux 
and those of Hodomyx are, that in Ptyssophorus most of the enamel 
folds reach all the way across the tooth ; the enclosed dentine is of 
nearly equal width throughout; the anterior loop of the first molar 
has an additional lobe, and the first and second external loops of the 
middle molar are more crowded and less distinctly separated (much 
as in Sigmodon8). The only one of these differences of more than 
8 The enamel pattern of the crowns of m 2 and :i of Ptyssophorus rlegans 
(fig. lc) is almost identical with that of young specimens of some living species 
of Sigmodon (fig. \d), hut the character of the teeth is different: In Sigmodon 
the crowns have hardly left (lie tuherculate condition ; the enamel is of unequal 
thickness, the loops are closely appressed, and the re-entrant angles are of super- 
ficial depth vertically; in Ptyssophorus the crowns are truly prismatic, perfectly 
flat on top. the loops well spaced, and the re-entrant angles reach from crown to 
alveolus. 1894.] 
NATURAL SCIENCES OF PHILADELPHIA. 
231 
specific weight is the length of the enamel folds, a character appa- 
rently due to antiquity, representing an earlier and more primitive 
stage in the evolution of the enamel pattern. In Ameghino’s single 
specimen the re-entrant angles or grooves between the folds extend 
vertically from crown to alveolus, as in the young of Neotoma and 
allied types. Whether they continue below the alveolus to the very 
root of the tooth as in the Arvicolines, we are not informed; but the 
characters of the jaw and molar crowns indicate that they do not. 
The specimen is apparently immature and the teeth are probably 
rooted or semi-rooted. 
Ptyssophorus elegans Ameghino. (Fig. 1, a, t>, and c.) 
Ptyssophorus elegans Ameghino, Mamiferos Fosiles Repub. Argentina, 1889, 
111. 112, and pi. 4. figs. 1, 1 c. 
Based on a fossil ramus of the mandible (right side) from the 
Pampean Pliocene deposits near Villa de Lujan, Province of Buenos 
Ayres. 
Specific characters. —Most of the characters have been given above 
in the generic diagnosis and need not be repeated. The anterior 
loop of m i has a lobe directed forward (see fig. lc). Ameghino 
states that the alveolar border is higher on the outer than inner side 
of the jaw, and that m i is nearly as large as m 2 and 3 together. 
He gives the following measurements: length of molar series on 
crowns, 5 mm.; on alveolus, 6; distance from incisor to m i, 5; 
height of ramus at m 3, 5; distance from front of incisor to back 
of last molar, 12. The incisor is short, but this may be an indi- 
vidual peculiarity. The hinder part of the mandible is broken off, 
so that the form of the angle and condylar ramus can only be in- 
ferred from allied forms. 
Ameghino’s figures are here reproduced (fig. 1, a, b, and c). 
Genus TRETOMYS Ameghino [Fossil]. 
(Fig. 2.) 
Tretomys Ameghino, Mam. Fos. Repub. Argent., 1889,119, pi. 4. figs. 16 and 16a. 
Type Tretomys atavns Ameghino, from Pampean Pliocene, Argentine Republic. 
Generic characters (based on Ameghino’s figures and description 
of part of maxillary bone including upper molar series, maxillary 
root of zygoma, and upper incisor).—Number of enamel folds as 232 
PROCEEDINGS OF THE ACADEMY OF 
[1894 
in other members of tlie subfamily (m 1 with 
three salient and two re-entrant loops on each 
side; m 2 and each with three salient and 
two re-entrant loops on outer side and two 
salient and one re-entrant loop on inner side); 
the re-entrant enamel folds from both sides 
stopping on or very near median line of teeth, 
and directed inward at nearly right angles to long axis of teeth, 
instead of obliquely backward as in the other genera ; m 2 and ;f 
subequal in size; m 1 slightly larger; anterior loop of m 1 pro- 
jecting on inner side as far as middle and posterior loops, and falling 
short of plane of other two on outer side (reversing the usual con- 
dition); zygomatic root of maxillary reaching back to posterior part 
of m 1 (anterior part in other genera). 
Tretomys atavns Amegliino. (Fig. 2.) 
Tretomys atavus Anieghino, Mamiferos Fosilos Rrpub. Argentina, 18Hlt, lilt, 
120, pi. 4, figs. 16 and 16a. 
Based on fossil fragment of maxillary bone containing molar 
series, and upper incisor, from near city of Cordoba, Argentine 
Republic. 
Specific characters.—Most of the characters have been given 
above, in the generic diagnosis. The molars are implanted squarely 
one in front of the other, the longitudinal axis of each tooth being 
the same as that of the series collectively. In the other genera the 
upper molars are implanted obliquely, the axis of m 2 and sloping 
outward as well as backward from the axis of the series as a whole. 
In Tretomys the posterior loop on the inner side and the anterior 
loop on the outer side of m 2 and :f are more largely developed 
than in the other genera, the result being that on each side all 
of the salient loops of the series end nearly on the same plane. 
Ameghino’s measurements of the molar series are: Series, 5 mm.; 
m *, 2 mm.; m 2, 1.6 mm.; m :i, 1.4 mm. The upper incisor is 
1 mm. broad and its face is very convex. 
Fig. 2. Tretomys 
alaz’us (from Ameg- 
hino). Left upper 
molars. 
Genus HODOMYS’ nob. 
Type Nenloma alleni Merriam, I’roc. Biol. Koe. Wash., VI f. Sept. l»7-lt>!» 
(Type from Manzanillo, Mexico). 
(PI. IX, Fign. 1-4, 7, 8, and Fig. 3, a, />, c, <7, in text.) 
M Hodotnys, from Mtr road, and /jit mouse, in allusion to the road-making 
habit of both species. 1894.; 
NATURAL, SCIENCES OF PHILADELPHIA. 
233 
Generic characters.—Upper molars much as in Neotoma,10 but 
crowns of m 1 and 2 with middle transverse loop divided by 
deepening of enamel fold on inner side; m 1 and 2 with four 
roots each; m 8 with three roots; lower molars with enamel folds 
reaching about half-way across tooth; m ;i shaped like letter S, 
Fig. 3. (x 5.) a and b. Hodomys alleni. c and d. H. vetulus. e and f. 
Xenomys nelsoni. 
a, c, e. Crowns of upper molars, b, d,f. Crowns of lower molars. 
with two salient and one re-entrant angle on eaeh side, with a ten- 
dency toward the subdivision of the antero-external loop by the 
development of a notch (or vertical sulcus) on its convexity ; upper 
incisors peculiarly excavated, apparently by the sharp point of the 
lower ones, leaving a deep cavity behind the enamel face, which is 
bordered laterally by the outer sides of the teeth. Cranium long 
and narrow, much as in Neotoma pennsylvanica, only narrower; 
audital bulke small, abruptly narrowed anteriorly, the narrow part 
produced obliquely inward, much as in Nectomys; inner side con- 
spicuously excavated by the carotid canal and foramen, which is 
considerably anterior to middle of bulla ; brain case narrow and 
long; spheno-palatine vacuities closed; mandible with coronoid 
notch more nearly vertical than horizontal ; condylar ramus high, 
10 Most of tlie accompanying description is drawn with reference to antithesis 
with Neotoma. Probably many of the characters apply to Ptyssophorus also, of 
which animal, unfortunately, the cranium and posterior part of the mandible 
are unknown. 234 
PROCEEDINGS OP TIIE ACADEMY OF 
[1894. 
curved strongly upward and inward; angle produced backward 
behind plane of condyle, and strongly inflected ; ramus of mandible 
thickened opposite molar teeth and abruptly narrowed and beveled 
to incisors. 
The principal characters that separate Hodomy* from Xenornyx are 
arranged antithetically in the following table:— 
XENOMYS. 
Posterior part of mandible 
only moderately expanded, short 
and cut away by deepening 
of coronoid and infracondylar 
notches (particularly the latter). 
Angular process decidedly an- 
terior to plane of condyle. 
Condyle overtopping coronoid. 
Anterior root of coronoid cut- 
ting plane of posterior loop of 
m 2* 
Horizontal ramus nearly 
straight below molar series. 
Cranium short. 
Squamosal not reaching supra- 
occipital. 
Audital bulla; enormously in- 
flated, wheel-shaped, parallel, 
broadest anteriorly. 
Audital bullae much longer 
than molar series and covering 
more than two-thirds distance 
from foramen magnum to post- 
palatal notch. 
Carotid canal inconspicuous, 
far behind middle of bulla. 
Orbital borders of frontals 
produced laterally, forming a 
shelf-like bead over orbits. 
HODOMYS. 
Posterior part of mandible 
long, large, and broadly ex- 
panded posteriorly; coronoid and 
infracondylar notches relatively 
shallow. 
Angular process produced 
backward behind plane of con- 
dyle. 
Coronoid overtopping condyle. 
Anterior root of coronoid cut- 
ting plane of anterior loop of 
m 3* 
Horizontal ramus decidedly 
convex downward below molar 
series. 
Cranium long and narrow. 
Squamosal articulating with 
supraoccipital. 
Audital bullae very small, 
subfusiform, abruptly narrowed 
anteriorly and produced ob- 
liquely forward toward median 
line. 
Audital bullae much shorter 
than molar series and covering 
only about one-third distance 
from foramen magnum to post- 
palatal notch. 
Carotid canal conspicuous, 
anterior to middle of bulla. 
Orbital borders of frontals 
upturned, not projecting over 
orbits. 1894.] 
NATURAL SCIENCES OF PHILADELPHIA. 
235 
XENOMYS (Coni.). 
Premaxillae produced ante- 
riorly in wing-like extensions 
reaching beyond nasals. 
Pterygoid fossa1 short—as 
broad as long. 
Postpalatal notch shorter than 
basisphenoid. 
Basioccipital very narrow. 
Lower molar series curved 
strongly outward anteriorly. 
HODOMYS (Coni.). 
Premaxillae without wing-like 
extensions. 
Pterygoid fossae long—twice 
as long as broad. 
Postpalatal notch longer than 
basisphenoid. 
Basioccipital broad. 
Lower molar series straight or 
nearly straight. 
Only two species of Hodomys are known. Both make extensive 
inosculating runways among the Agaves and other plants on the 
brushy side hills where they live. This habit is unknown in the 
allied genera Neotoma. and Xenomys. Neotoma builds houses or 
amasses large piles of sticks, cactus spines, or other rubbish ; 
Xenomys lives in hollow trees ; Hodomys is not known to do either. 
Hodomys alleni (Merriam). (PI. IX, figs. 1-4; and text fig. 3, a and b.) 
Neotoma alleni Merriam, Proc. Biol. Soc. Washington, VII, Sept. 1892,167-169- 
(Type from Manzanillo, Mexico.) 
General characters.—Size large (larger than any known species of 
Neotoma) ; ears rather large; tail shorter than head and body, 
blackish, sparsely haired, the annulations and scales distinctly visible 
on both sides. 
Color.—Upper parts from forehead to base of tail deep fulvous or 
tawny-ferruginous ; nose and sides of face mouse-gray, tinged with 
bluish in some specimens; under surface whitish, the tips of the hair 
only being white, the plumbeous basal part showing through ; up- 
per surfaces of feet whitish, more or less clouded with dusky ; tail 
blackish all round. 
Cranial characters.—Skull very long and narrow; angular; 
orbital margins of frontals nearly parallel and strongly upturned, 
with tendency to develop an upturned point opposite middle of 
orbital fossa; interparietal shield quadrate; nasals produced and 
pointed anteriorly, truncate or emarginate posteriorly. (Principal 
characters given under generic diagnosis and not repeated here. ) 
Measurements of type (taken in flesh).—Total length, 472 mm; 
tail vertebrae, 225; hind foot, 4(3; ear, 29 (in dry skin). 236 
Cranial measurements of type.—Total length, 54 mm ; basal 
length, 4(5.5; basilar length of Hensel, 44; zygomatic breadth, 27 ; 
upper molar series on crowns, 10. 
Hodomys vetulus sj). nov. (Text fig. 3, c and d.) 
Type from Tehnacan, Puebla, Mexico. No. 53,(55(5 $ ad., 1. S. 
Nat. Museum, Department of Agriculture Collection. Collected 
May 8, 1893, by E. W. Nelson. (Original number 4,784.) 
General characters.—This animal bears no close resemblance to 
any known species except Hodomys alleni from Mazanillo (on the op- 
posite side of Mexico), with which it shares the remarkable S-shaped 
last lower molar, peculiar audital bulla?, closed sphenopalatine vacui- 
ties, and many other characters. It is much smaller than alleni, has 
a bicolor instead of concolor tail, white instead of dusky hind feet, 
and differs also in cranial characters. 
Color.—Upper parts dull fulvous from point between eyes to rump, 
plentifully mixed with black hairs; face gray; fore and hind feet 
white; tail bicolor, blackish above, soiled white beneath ; under 
parts whitish, clouded from plumbeous under fur and washed with 
dull fulvous on sides of belly (and in one specimen on breast also). 
Crania! characters.—Skull similar to that of Hodomys alleni, but 
smaller, shorter, less angular, and differing further in the following 
characters: rostrum and nasals shorter ; nasals narrower posteriorly; 
interparietal shield lass quadrate and more elongated transversely; 
incisive foramina shorter (falling considerably short of plane of m 1); 
palate proportionally longer ; audital bulhe smaller; frontals broader 
posteriorly and less upturned along orbital margins ; mandible less 
expanded posteriorly. 
Dental characters.—Similar to H. alleni, but m 1 broader and 
shorter; the antero-external loop larger; postero-internal loop less 
completely divided ; m 3 broader and shorter; more perfectly 
S-shaped, and without trace of antero-external sulcus. 
Measurements (taken in flesh).—Type: Total length, 380 mm; tail 
vertebrae, 1(56; hind foot, 38. Ear from anterior base, 29 (in dry 
skin). Average measurements of 4 specimens from type locality : 
Total length, 365; tail vertebrae, 163; hind foot, 38. 
CraniaI measurements of type.—Total length, 47; basal length, 41; 
basilar length of Hensel, 39; zygomatic breadth, 25; upper molar 
series on crowns, 9. 
PROCEEDINGS OF THE ACADEMY OF 
[1894. 1894.] 
NATURAL SCIENCES OF PHILADELPHIA. 
237 
Mr. Nelson states that this species is rather common about the 
foot of the low cliffs and rocky ledges on the hillsides east of Te- 
huacan, and that it lives in dense patches of Agave. He says : “ It 
has the habit of making roads about its haunts, very much after the 
manner of N. alleni. Well-defined trails were found leading along 
the hillside from roek to rock or to the cover of Agave patches, and 
between neighboring groups of these plants. Under the shelter of 
a maguey patch a network of trails could he frequently found by 
forcing ones way among the spiny leaves. Like X. alleni, these 
animals did not take grain bait, and were caught by placing traps 
in their trails. No signs of the nest building habit, so common in 
the genus Neotoma, were observed.” 
Genus XENOMYS Merriam. 
Xenomys Merriam, Proc. Biol Soc. Washington, VII, Sept. 1892, 1 .">9-1 (13 (Type 
from Hacienda Magdalena, Colima, Mexico). 
Generic characters.—Skull murine; short; audital bullae greatly 
enlarged and inflated, broader anteriorly than posteriorly, wheel- 
shaped, parallel, carotid foramen posterior to middle of bulla and 
inconspicuous; squamosal not reaching supraoccipital but ending 
anterior to plane of auditory meatus, except the slender posterior 
spicule which reaches over meatus to mastoid ; orbital margins of 
frontals produced laterally forming projecting supraorbital beads ; 
lachrymals large ; interparietal large and transversely elongated ; 
premaxillm produced anteriorly forming a wing-like extension on 
each side of anterior nares; angle of mandible short, moderately 
expanded vertically, inflected; condylar ramus long and high, over- 
topping coronoid process ; molars large and heavy; truly rooted 
(upper with three roots each; lower with two roots each); crowns 
prismatic, made up of broadly rounded alternating salient loops and 
open re-entrant angles or interspaces; crown of m 3, shaped in 
general like letter S but somewhat angular (fig. 4). 
Externally, Xenomys resembles a small, highly colored wood rat, 
with rather soft pelage and a large whitish spot over each eye. The 
tail is nearly as long as the head and body. Nothing is known of 
the habits of these animals, except that they are nocturnal and live 
in hollow trees. 
Xenomys agrees with Hodomys in having the mandibular symphysis 
rather long, straight and upturned; the condylar ramus very long, 
(PI. IX, figs. 10-13; and text fig. 3, e and /, and fig. 4.) 238 
PROCEEDINGS OF THE ACADEMY OF 
[1894. 
and curving strongly upward and inward; the coronoid notch nearly 
vertical; the angle inflected (but not produced backward so far as 
in Hodomys) ; the incisors slender, meeting in a single sharp point; 
the molars very large; and m a, shaped like the letter S. Xenomys 
differs from Hodomys in having the mandible greatly reduced poste- 
riorly; the condylar ramus longer and more slender, overtopping the 
coronoid, and both coronoid and infracondylar notches larger at the 
expense of the posterior part of the ramus, which is greatly reduced 
thereby. In Xenomys the anterior base of the coronoid process 
arises more anteriorly from the horizontal ramus, hiding the whole 
of the last molar and posterior loop of the middle molar, while in 
Hodomys it arises further back, exposing the anterior loop of the 
last molar. (In Neotoma the line commonly falls between m ■> and 
.{; in Ptyssophorus, according to Ameghino’s figure, it apparently is 
further back, exposing most of m 3.) 
Xenomys nelsoni Merriam. (PI. IX, figs. 10-13; and text figs. 3, e and /, and 
fig. 4.) 
Xenomys nelsoni Merriam, Proc. Biol. Soc. Washington, VII, Sept. 1802, 161- 
163. Type from Hacienda Magdalena, Colima, Mexico. 
General characters.—Size about that of a half or two-thirds grown 
rat, or nearly equaling Neotoma mexicana; tail a little shorter than 
head and body, well haired, particularly above; face ornamented by 
a distinct whitish spot over each eye and a less distinct one under 
each ear; color of upper parts rich fulvous; under parts white; ears 
about half as long as the head and nearly naked (sparsely clothed 
with fine, inconspicuous hairs) ; whiskers reaching back to shoulders; 
fur soft. 
Color.—Upper parts fulvous or tawny-rufous, palest on the head 
and brightest over the rump, flanks, and hips; back sparsely mixed 
with black-tipped hairs; an ill-defined dusky ring around each eye, 
above which is a whitish spot about as large as the eye itself; a less 
distinct whitish spot just below the inferior root of the ear; upper 
lips white, the white color extending up on the cheeks more than 
half-way to the eyes; sides of face below eyes and ears washed with 
fulvous; whiskers blackish; tail concolor, dark umber-brown all 
round ; upper surfaces of feet whitish , more or less clouded with 
dusky (varying considerably in the three specimens); under parts 
creamy white to the very roots of the hairs except along the sides 
of the belly, where the basal part of the fur is plumbeous ; line of 1894.] 
NATURAL SCIENCES OF PHILADELPHIA. 
239 
demarkation between colors of upper and lower parts everywhere 
sharp and distinct. 
Cranial and dental characters.—Most of the cranial and dental 
characters have been already given under the head of the genus 
and need not be here repeated. The rostrum is short and the ascend- 
ing branches of the premaxillae hardly reach as far back as the nasals. 
Molars large and broad ; m 1 more than half as broad as long and 
Fig. 4. Xenomys nelsoni Type. Upper and lower 
molar crowns, (x 7.) 
curving outward anteriorly ; m j with anterior half bent strongly 
outward, the anterior loop looking outward instead of forward; m 3, 
S-shaped, with a small and nearly closed triangle on outer side of 
convexity, thus having an anterior loop projecting inward, a poste- 
rior loop projecting outward, and a re-entrant angle or loop on each 
side, the outer of which is the shallower and more posterior in posi- 
tion ; both of the re-entrant angles are directed obliquely forward as 
well as toward the opposite side of the tooth (for further details see 
fig. 4). 
Measurements of type (taken in flesh).—Total length, 300 mm; 
tail vertebrae, 143; hind foot, 30; ear 22 (in dry skin). 
Cranial measurements of type.—Total length, 40.5; basal length, 
35; basilar length of Hensel, 33; zygomatic breadth, 21; upper molar 
series on crowns, 8. 
Genus NEOTOMA Say and Ord. 
Neoloma Say and Ord, Journ. Acad. Nat. Sci. Phila., IV, pt. 2, 1825. 345, 346, 
pis. XXI and XXII Type Mus floridana Ord, from eastern Florida. 
Generic characters.'1—Crown of m 3 composed of two transverse 
11 The characters here given are selected with reference to antithesis with 
Ptyssophorus, Hodomys, and Xenomys. 240 
PROCEEDINGS OF THE ACADEMY OF 
[1894. 
loops (with the addition in rare cases of a narrow antero-external 
loop), never S-shaped (fig. 5); m 1 and - with middle loop un- 
divided (reaching completely across tooth); molar series relatively 
short; condylar ramus low and directed obliquely backward ; coro- 
noid notch horizontal or nearly so [nearly vertical in Xenomys and 
Hodomys] ; angle of mandible only moderately inflected ; symphysis 
relatively short and sloping strongly forward. 
The accompanying illustration (fig. 5) shows the two extremes 
in pattern of m 1, and differences in the crowns of the other molars 
also. The dominant type of m 1 throughout the genus is similar 
to that of N. tenuicauda (fig. 5, c), a member of the mexicana series. 
Fig. 5. a and c. Upper molar crowns, b and d. Lower molar crowns. 
a. b. Neotoma deserlorum Merriam. Death Valley, Calif., No. 34138. '. 
(x5.) c. d. Neolotna tenuicauda Merriam. Sierra Nevada, Jalisco, Mexico. 
45629 ?. Type, (x 5). 
Neotoma is not in any sense a highly specialized type, hut it is a 
very compact genus, its most divergent branches hardly meriting 
subgeneric recognition. Some of its members point strongly toward 
derivation from Hodomys, as may be seen in the Nectornys-Uke au- 
dital bulla; and other cranial characters of Neotoma penmylvanica, 
and in the high, upturned condyle of the mexicana group, but the 
immediate antecedent forms leading up to Neotoma from llodomys, 
or some similar type, are not known. The oldest forms of which we 
have any knowledge, those from the cave deposits of Missouri, Ken- 
tucky, Virginia, and Pennsylvania, are fully modernized species of 
Neotoma proper. 
Of the living species, N. penmylvanica may he regarded as the 
most primitive, since it possesses several characters, not shared bv 
the others, that point back to Hodomys. Moreover, penmylvauiea is 
more nearly intermediate between the two subgenera—Neotoma 
proper and Teonoma—than any other known species, indicating that 1894.] 
NATURAL, SCIENCES OF PHILADELPHIA. 
241 
the differentiation of the trunk line into these two groups proceeded 
from a form at least very similar to ptnnsylvanica. N. pennsylvanica 
resembles Hodomys in the peculiar shape of the audital bullte (which 
are abruptly narrowed anteriorly), in the nearly closed spheno-pala- 
tine vacuities, in the posterior production of the angle of the madible, 
and in the strong inward and upward curvature of the condylar 
ramus. It resembles Teonoma in the form of the sagittal area, which 
is kite-shaped, narrow, sharply angular, broadest far back (on or 
near plane of interparietal), whence its sides curve abruptly inward 
and backward to the sides of the interparietal shield. It resembles 
Teonoma further in the tendency to closure of the spheno-palatine 
vacuities,12 the great length of the rostrum, and the presence of a 
long trough-like depression which occupies the entire length of the 
frontal and hinder part of the nasals. 
That the absence of the spheno-palatine vacuity is a primitive 
character—or perhaps it would be better to say, that the presence of 
a vacuity is a modern character—is indicated by the following facts: 
(1) The ancestral genus Hodomys has no vacuity ; (2) Xenomys, an 
early offshoot from the primitive Neotomine stem, has very small 
vacuities ; (3) Teonoma, an older type than Xeotoma proper, has the 
vacuities closed or partly open ; (4) Xeotoma pennsylvanica, the least 
differentiated known member of the modern genus, has the vacuities 
partly closed ; and finally (5) some of the modernized species have 
the vacuities closed in early life though fully open in the adult.13 
In its geographic distribution the genus is restricted, so far as 
known, to North America north of Duehas, Guatemala.14 The spe- 
cies are most numerous in Mexico and the southern United States, 
'fhe total number of species here recognized, including the subfossil 
.V. magister, is 22, in addition to which 10 subspecies are admitted. 
It is probable that a few additional species will be added, and that 
some of the members of the mexicana group will be reduced to sub- 
specific rank. 
12 But there is this difference : The thin wing or lamella of bone which 
closes or partly closes the vacuity in Teonoma is derived wholly from the pala- 
tine, while in N. pennsylvanica it is made up almost equally of palatine and 
pterygoid. In the latter species the suture between the palatine and pterygoid 
moieties is on the plane of the suture between the basisphenoid and presphenoid. 
u Allen has recently shown this to be the case in N. micropus (Bull. Am. 
Mils Nat. Hist., N. Y., VI, 1894, 239). 
14 The Guatemala species (N. ferruginea Tomes) has not been seen by me and 
may not he a true Neoloma. 242 
PROCEEDINGS OF THE ACADEMY OF 
[181)4. 
In 1843, J. E. Gray separated the bushy tailed from the round 
tailed species, proving the name Teonoma for the former. In a 
recent communication I adopted the name for a subgenus, and de- 
fined the resulting two subgenera as follows:— 
Subgenus NEOTOMA Say and Ord, 1825. 
Neotoma Say and Ord, Jouni. Acad. Nat. Sci. l’liila., IV, pt. 2, 1S25. .145, 34H, 
pi. XXJ, XXII. Type MusJioridana. Ord, from eastern Florida. 
Tail commonly round, scant-haired and tapering, hut in one 
species moderately bushy; hind feet small or moderate. 
Rostrum of moderate length, not more than one-third the length 
of cranium; sagittal area usually rounded, the broadest part always 
considerably anterior to plane of interparietal, whence the sides curve 
gradually backward to interparietal shield; spheno-palatine vacuities 
always open. 
Subgenus TEONOMA Gray, 1843 
Teonoma Gray, List Spec. Mainm. British Museum, 1H43, 117. Type Neotoma. 
cinerea drummondi (Richardson), from the Rocky Mts. in lat. 57°N. 
Tail very large, bushy, and somewhat distichous, like a squirrel’s; 
hind feet very large. 
Rostrum much elongated, measuring more than one-third the total 
length of cranium; posterior roots of zygomata widely spreading; 
sagittal area long, narrow, and sharply angular, its broadest part 
far back, on or nearly on plane of anterior border of interparietal, 
whence the sides bend abruptly back to interparietal shield; spheno- 
palatine vacuities closed or open. 
In the same communication I proposed, for convenience in arrang- 
ing the species, to subdivide Neotoma proper into four minor groups, 
“none of which is worthy of the distinction of subgeneric rank. 
These groups may be designated, from a typical species in each, as 
follows: (l)tlie leucodon group; (2) the meximna group ; (3) the 
desertorum group, and (4) the arizonte group.” 
In a recent paper on Cranial Variations in Neotoma micropus,ls 
Dr. J. A. Allen criticises ray use of the color of the teeth as a sub- 
ordinate character, and goes on to state that the range of individual 
variation in color in his series of N. micropus “covers the whole 
range of variation for the genus.” His subsequent remarks show 
15 Bull. Am. Mus. Nat. Hist.. N. Y , VI, Aug. 3, 1K!»4, 243, 244. 1894.] 
NATURAL SCIENCES OF PHILADELPHIA. 
243 
a total misapprehension of my meaning, for instead of speaking of 
the color of the teeth themselves he refers to the dirty coating on the 
outside of the teeth. He says: “The black coloring consists to a 
large extent of a superficial incrustation which tends to scale off in 
flakes in the prepared skull, and its absence apparently may be due 
sometimes to removal in the process of cleaning the skull for the 
cabinet. In other words, the blackness is to some extent an acci- 
dental or pathological condition, due probably more or less to the 
particular character of the food or to the health of the animal.” 
But for this perverse interpretation of my very plain statement it 
would not be necessary to explain that when I said “color of teeth 
white or nearly white” I meant the teeth—the osteodentine and en- 
amel—not the dirty deposit that sometimes collects on the outside of 
the teeth. But after all, the peculiarity is one of little consequence 
and was only mentioned by me after enumerating the characters by 
which members of the leucodonHi group may be distinguished from 
others. 
The following list of the 22 species and 10 subspecies recognized 
by me contains under each name: (1) reference to the original de- 
scription; (2) the principal synonymy; (3) the type locality; (4) the 
known geographic distribution. 
Descriptions of the species are not added because they are included 
in a more formal and fully illustrated revision of the genus which 
will be published later. 
Neotoma leucodon Merriam. 
Neotoma leucodon Merriam, Proc. Biol. Soc. Wash., IX, July 2, 1894, 120. 121. 
Type locality: San Luis Potosi, Mexico. 
Geographic distribution.—Upper part of Lower Sonoran Zone in 
Central Mexico, from Berriozabal, Zacatecas, easterly to southern 
San Luis Potosi, and thence southeast to Perote, Vera Cruz. 
Neotoma latifrons Merriam. 
Neotoma latifrons Merriam, Proc. Biol. Soc. Wash., IX, July 2, 1804, 121. 
Type locality: Querendaro, Michoacan, Mexico. 
Geographic distribution.—Valley of Querendaro, south side of 
Lake Cuitzeo, Michoacan, Mexico (range unknown.) 
,,! Named, as stated, after A7". leucodon, a central member of the group, not 
because all the specie's have white teeth. 244 
PROCEEDINGS OF THE ACADEMY OF 
[1894. 
Neotoma micropus Baird. 
Neotonia micropus Baird, I’roc. Acad. Nat. Sci. Phila., April, 1855. 333 (from 
Charco Escondido, Tamaulipas.17) Mammals of N. Am., 1857, 402-495. Allen, 
Bull. Am. Mus. Nat. Hist., N. Y., Ill, No. 2, June, 1891, 282-285. 
Neotoma micropus canescens Allen, Bull. Am. Mus. Nat. Hist., III. No. 2, 
June, 1801,285-287 (from N. Beaver Creek, Pan Handle of Oklahoma). 
Type locality; Charco Escondido,17 Tamaulipas, Mexico (100 kilo- 
meters or 62 miles west of Matamoras, and 44 kilometers or 27 miles 
south of Reynosa.) 
Geographic distribution.—Eastern subdivision of Lower Sonoran 
Zone from San Fernando, Tamaulipas, northward to the Fan Han- 
dle of Oklahoma, and westward to the Staked Plains ; in the Rio 
Grande Valley west to El Paso; and in the Pecos Valley to Eddy, 
New Mexico. 
Neotoma baileyi Mcrriam. 
Neotoma baileyi Mcrriam, Proc. Biol. Soc. Wash., IX, July 2, 1891, 123. 
Type locality: Valentine, Nebraska. 
Geographic distribution.—Probably Great Plains subdivision of 
Upper Sonoran Zone in southern South Dakota, Nebraska, and 
Kansas. 
Neotoma floridana (Ord). 
Mus floridana Ord, Bull. Soc. Philomath, Dec. 1818, 181-182 
Type locality: Florida. 
Geographic distribution.—Austroriparian Fauna of South Atlan- 
tic and Gulf Coasts and lower Mississippi Valley. 
Neotoma pennsylvanica Stone. 
Neotoma pennsylvanica Stone, Proc. Acad. Nat. Sci. Phila., Feb. 1893, HM8. 
Type locality: South Mountain, Cumberland Co., Pennsylvania. 
Geographic distribution.—Allegheny Mountain region of Pennsyl- 
vania, and probably the whole of the southern Alleghenies; north to 
southern New York. 
Neotoma magister Baird. 
Neotoma magister Baird, Mam. N. Am., 1857, 498. 
Type locality: Bone Caves near Carlisle (between North and 
South Mountains), Pennsylvania. 
17 Two specimens were mentioned in the original description, an adult male 
from Charco Escondido, and a very young specimen in poor condition from Santa 
Rosalia, Chihuahua. The original description is based wholly on the Charco 
Escondido specimen, which, therefore, must he taken as the type of the species. 
The Santa Rosalia animal is somewhat aberrant, as shown by additional specimens. 1894.] 
Geographic distribution.—Pleistocene cave deposits of Pennsyl- 
vania and Virginia. Remains assumed to belong to the same spe- 
cies have been found in caves in Kentucky and in the Ozark Hills 
of Missouri. 
Neotoma mexicana Baird. 
Neotoma mexicana Baird, Proc. Acad. Nat. Sci. Phila., VII, 1855, 333. 
Type locality: [Mountains] near Chihuahua, Mexico. 
Geographic distribution.—Hills and lower mountain slopes (usu- 
ally pine covered) of Transition Zone in eastern New Mexico, 
southwestern Texas (Davis Mountains to Paisano), and Chihuahua, 
Mexico. 
Neotoma mexicana bullata Merriam. 
Neotoma mexicana bullata Merriam, Proc. Biol. Soc. Wash., IX, July 2, 1894, 
122-123. 
Type locality: Santa Catalina Mountains, Arizona. 
Geographic distribution.—Known only from the Santa Catalina 
Mountains in southern Arizona. 
Neotoma pinetorum Merriam. 
Neotoma pinetorum Merriam, Proc Biol. Soc. Wash., VIII, July 31, 1893, 111, 
112. 
Type locality: San Francisco Mountain, Arizona. 
Geographic distribution.—The pine covered plateau of Arizona 
(Transition Zone). 
Neotoma tenuicauda Merriam. 
Neotoma tenuicauda Merriam, Proc. Biol. Soc. Wash., VII, Sept. 29, 1892, 169, 
170. 
Type locality: North Slope of Sierra Nevada de Colima. 
Geographic distribution. — Sierra Nevada de Colima, Jalisco, 
Mexico (probably in Transition Zone). 
Neotoma orizabae Merriam. 
Neotoma orizabcE Merriam, Proc. Biol. Soc. Wash., IX, July 2, 1894, 122. 
Type locality: Mt. Orizaba, Puebla, Mexico. 
Geographic distribution.—Mt. Orizaba, Mt. Malinche, and Cofre 
de Perote, Mexico (probably in Transition Zone.) 
Neotoma fulviventer Merriam. 
Neotoma fulviventer Merriam, Proc. Biol. Soc. Wash., IX, July 2, 1894, 121 
122. 
Type locality: Toluca Valley, Mexico. 
Geographic distribution.—Toluca Valley, Mexico. 
NATURAL SCIENCES OF PHILADELPHIA. 
245 246 
[1894. 
Neotoma torquata Ward. 
Neotoma torquata Ward, Am. Naturalist, XXV, Feb. 1891, 160, 161. 
Type locality: [An abandoned tunnel] between Tetela del Volcan 
and Zacualpan Amilpas, Morelos, Mexico. 
Geographic distribution.—Mountains of the states of Mexico and 
Morelos (south of the valleys of Mexico and Toluca). 
Neotoma ferruginea Tomes. 
Neotoma ferruginea Tomes, Proc. Zool. Soc. London, 1861, 282-284. 
Type locality: Duenas, Guatemala. 
Geographic distribution. — Region about Duenas, Guatemala. 
Range unknown. 
Note.—I have not seen N. ferruginea; it may not belong here 
at all. 
Neotoma fallax Merriam. 
Neotoma fallax Merriam, Proc. Biol. Soc. Wash., IX, July 2, 1894, 123, 124. 
Type locality: Gold Hill, Boulder Go., Colorado. 
Geographic distribution.—Eastern base of Rocky Mountains in 
Colorado (up to about 7,000 feet altitude, where it is replaced by 
N. orolestes). 
Neotoma bryanti Merriam. 
Neotoma bryanti Merriam, Am. Nat. XXI, No. 2, Feb. 1887, 191-193. 
Type locality: Cerros Island, Lower California. 
Geographic distribution.—Cerros Island, Mexico (off Lower Cali- 
fornia). 
Neotoma fuscipes Baird. 
Neotoma fuscipes (Cooper MS.) Baird, Mam. N. Am., 1857, 495, 496 (from Peta- 
luma, Calif.). 
Neotoma monochroura Rhoads, Am. Naturalist, XXVIII, Jan. 1894, 67, 68 
(from Grants Pass, Josephine Co., Oregon). 
Neotoma splendens True, Proc. IT. S. Nat. Museum, XVII, No. 1006, 1, 2 
[Author’s separates issued June 27, 1894], (from Marin Co., Calif.). 
Type locality: Petaluma, Sonoma Co., California. 
Geographic distribution.—Coast region of California and Oregon, 
from a little south of Monterey Bay northward to the Columbia 
River (Transition Zone). 
Neotoma fuscipes macrotis (Thomas). 
Neotoma macrotis Thomas, Ann. and Mag. Nat. Hist., 6th ser., XII, Sept. 1893, 
234,235 (from San Diego, California). 
Neotoma macrotis simplex True, Proc. U. S. Nat. Museum, XVII, No. 1006, 2 
[Author’sseparates issued June 27,1894], (from Old Ft. Tejon, California). 
Type locality: San Diego, California. 
PROCEEDINGS OF THE ACADEMY OF 1894.] 
NATURAL SCIENCES OF PHILADELPHIA. 
247 
Geographic distribution.—Coast region (including coast ranges) 
of California, south of Monterey Bay (in upper Sonoran and Transi- 
tion Zones). 
Neotoma fuscipes streatori Merriam. 
Neotoma fuscipes streatori Merriam, Proc. Biol. Soc. Wash., IX, July 2, 1894, 
124. 
Type locality: Carbon dale, Amador Co., California. 
Geographic distribution.—West slope of Sierra Nevada in Cali- 
fornia (including mountain region generally of northeast California 
except higher elevations.) Upper Sonoran and Transition Zones. 
Neotoma fuscipes dispar Merriam. 
Neotoma fuscipes dispar Merriam, Proc. Biol. Soc. Wash., IX, July 2, 1894, 
124, 125. 
Type locality: Lone Pine, Owens Valley, California. 
Geographic distribution.—East base of Sierra Nevada in Owens 
Valley, California (and probably along western edge of Mohave 
Desert also). Upper Sonoran Zone. 
Neotoma desertorum Merriam. 
Neotoma desertorum Merriam, Proc. Biol. Soc. Wash., IX, July 2, 1894, 125, 
126. 
Type locality: Furnace Creek, Death Valley, California. 
Geographic distribution.—Mohave and Colorado Deserts and Sono- 
ran deserts generally of eastern California, Nevada, and western 
Utah (north to East Humboldt Valley, Nevada, and Kelton, 
Utah.) Upper and lower Sonoran Zones. 
Neotoma desertorum sola Merriam. 
Neotoma desertorum sola Merriam, Proc. Biol. Soc. Wash., IX, July 2, 1894, 
126. 
Type locality: San Emigdio, Kern Co., California. 
' Geographic distribution.—Head of San Joaquin Valley, Cali- 
fornia. 
Neotoma intermedia Rhoads. 
Neotoma intermedia Rhoads, Am. Naturalist, XXVIII, Jan. 1, 1864, 69, 70. 
(from Dulzura, San Diego Co., California). 
Neotoma calif or nica Price, Proc. Calif. Acad. Sci., 2d ser., III, May 9,1894,154- 
156, pi. XI (from Bear Valley, San Benito Co., California). 
Neotoma intermedia gilva Rhoads, Am. Naturalist, XXVIII, Jan. 1, 1894, 69 
(from Banning. California). 
Neotoma venusta True, Proe. U. S. Nat. Museum, XVII, No. 1006, 2 [Author’s 
separates issued June 27th, 1894], (from Carrizo Creek, San Diego Co., 
California). 
Type locality: Dulzura, San Diego Co., California. 248 
PROCEEDINGS OF THE ACADEMY OF 
[1894. 
Geographic distribution.—The typical form inhabits the valleys 
and lower slopes of the coast ranges of California south of Monterey 
Bay (specimens examined from Bear Valley, San Benito Co. ; 
Priest Valley, Monterey Co.; San Luis Obispo; San Fernando; San 
Bernardino Mt. and Valley; San Jacinto Valley, and Dulzura). 
A slightly paler form (subspecies gilva Rhoads = venvsta True) in- 
habits San Gorgonio Pass and the western edge of the Colorado 
Desert (specimens examined from Whitewater Ranch, Palm Springs, 
Cabazon, Carrizo Creek, Baregas Spring, and Vallecitas). Upper 
Sonoran. 
Neotoma intermedia melanura Merriam. 
Neotoma intermedia melanura Merriam, Proc. Biol. Soc. Wash., IX, July 2, 
1804, 120, 127. 
Type locality: Ortiz, Sonora, Mexico. 
Geographic distribution. — Sonora, Mexico, near west base of 
Sierra Madre. Upper Sonoran. 
Neotoma intermedia albigula Hartley. 
Neotoma albigula Hartley, Proc. Cal. Aead.Sci., 2d ser., Ill, May 0, 1804, 157- 
150, pi. XII. 
Type locality: Vicinity of Fort Lowell, Arizona. 
Geographic distribution.—Lower Sonoran Zone in southern and 
western Arizona. 
Neotoma intermedia angusticeps Merriam. 
Neotoma intermedia angusticeps Merriam, Proc. Biol. Soc. Wash., IX, July 2, 
1804, 127. 
Type locality: S. W. corner Grant Co., New Mexico (only 4 
miles from Mexican boundary). 
Geographic distribution.—Southwestern New Mexico, and doubt- 
less also adjacent valleys of N.W. Chihuahua, Mexico (in Lower 
Sonoran Zone). 
Neotoma arizonae Merriam. 
Neotoma arizonce Merriam, Proc. Biol. Soc. Wash., VIII, July 31, 1803, 110, 
111. 
VNeotoma lepida Thomas, Ann. and Mag. Nat. Hist., 8th ser., XII, Kept. 
1803, 235 (from Utah). 
Type locality: Kearns Canon, Apache Co., Arizona. 
Geographic distribution.—Tusayan or Moki region in northeastern 
Arizona, northwestern New Mexico, southeastern Utah, and prob- 
ably southwestern Colorado. Sonoran. 1894.] 
NATUKAL SCIENCES OF PHIEADELPHIA. 
249 
Neotoma cinerea (Ord.) 
“Mus cinereus Ord, Guthrie’s Geography, 2d Am. Ed., II, 1815, 292” 
(based on description of Lewis and Clark, Paul Allen Ed., 1814, Vol. I, pp. 289, 
290.) 
Type locality: Near Great Falls, Montana. 
Geographic distribution.—Northern Rocky Mt. region in Transi- 
tion and Boreal Zones, from Utah and Wyoming northward; east to 
Black Hills and plains of North Dakota west of Missouri River; 
west in southern British Columbia to Cascade Range, and south 
throughout the Sierra Nevada to Mt. Whitney in southern Cali- 
fornia. 
Neotoma cinerea occidentalis (Baird). 
Neotoma occidentalis (Cooper MS.) Baird, Proc. Acad. Nat. Sci. Phila., VII, 
1855, 335. 
Neotoma cinerea occidentalis Merriam, Mammals of Idaho, N. Am. Fauna, 
No. 5, Aug. 1891, 58. 
Type locality: Shoalwater Bay, Washington. 
Geographic distribution. — Pacific coast region of Oregon and 
Washington and thence easterly over the lava beds to the Snake 
Plains of east-central Idaho (Transition and Upper Sonoran Zones). 
Neotoma cinerea drummondi (Richardson). 
My ox us drummondii Richardson, Zool. Journ., Ill, 1828, 517, 518. 
Neotoma drummondii Richardson, Fauna Boreali-Am., 1829, 137-140. 
Type locality: Rocky Mts., British Columbia (lat. 57°). 
Geographic distribution.—Eastern British Columbia and adjacent 
parts of western Canada north of the range of cinerea. Exact dis- 
tribution unknown. Boreal (probably Hudsonian). 
Neotoma orolestes Merriam. 
Neotoma orolestes Merriam, Proc. Biol. Soc. Wash., IX, July 2, 1894, 128. 
Type locality: Saguache Valley (20 miles west of Saguache, Colo- 
rado). 
Geographic distribution. — Rocky Mts. of Colorado and New 
Mexico (southeast of range of N. cinerea'). Boreal. 250 
PROCEEDINGS OF THE ACADEMY OF 
[1894. 
Species and Subspecies of Neotom a. 
leucodon 
latifrons 
micropus 
baileyi 
floridana 
pennsylvanica 
magister 
leucodon group 
mexieana 
“ bullata 
pinetorum 
tenuicauda 
Orizaba1 
fulviventer 
fall ax 
fuscipes 
“ macrotis 
“ streatori 
‘ ‘ dispar 
bryanti 
? ferruginea18 
? torquata18 
Subgenus NEOTOM A 
mexieana group 
desertorum 
“ sola 
intermedia 
“ melanura 
“ albigula 
‘ ‘ angusticeps 
desertorum group 
arizonse group 
arizonse 
cinei'ea group 
cinerea 
“ 
“ drummondi 
orolestes 
Subgenus TEONOMA 
18 Ar. torquata and ferruginea I have not seen, hence their relations may not 
he as here indicated. 1894.] 
NATURAL SCIENCES OF PHILADELPHIA. 
251 
ILLUSTRATIONS. 
PLATE IX. 
(Figures natural size.) 
Figs. 1-4, 7, 8. Hodomys alleni, 9, 44,631, Manzanillo, Mexico. 
1, skull from above ; 2, same from left side ; 3, same from 
below ; 4, mandible from left side ; 7, same from below; 
8, same from above. 
Figs. 5, 6, 9. Neotoma. 
5, mandible from left side; 6, same from below ; 9, same from 
above. 
Figs. 10-13. Xenomys nelsoni, $, 45,287, Hacienda Magdalena, 
Colima, Mexico. 
10, skull from above; 11, same from left side; 12, same from 
below ; 13, mandible from left side. 
TEXT FIGURES. 
Fig. 1, a, b, c. Ptys8ophoru8 elegans (from Ameghino). 
a, right ramus of mandible, outer side. Nat size. 
b, “ “ “ “ inner side. Enlarged. 
c, crowns of right lower molars. 
d, Sigmodon hispidns, crowns of right lower molars. Enlarged. 
c, Hodomys alleni, “ “ “ “ “ “ 
Fig. 2. Tretomys atavus, left upper molars enlarged (from 
(Ameghino). 
Fig. 3, a and b, Hodomys alleni. 
a, crowns of left upper molars, (x 5.) 
b, “ “ “ lower molars. 
c and d. Hodomys vetulus. 
c, crowns of left upper molars, (x 5. ) 
d, “ “ “ lower molars. 
e and f. Xenomys nelsoni. 
e, crowns of left upper molars, (x 5.) 
/, “ “ “ lower molars. 
Fig. 4. Xenomys nelsoni. Type No. j~j*, S, ad. 
Hacienda Magdalena, Colima, Mexico. 
a, upper molar series, (x 7.) 
b, lower molar series. 252 
PROCEEDINGS OF THE ACADEMY OF 
[1894. 
Fig. 5, a and b. Neotoma desertornm. Death Valley, California, 
No. 34,138, $, ad. (x 5.) 
a, upper molar series. 
b, lower molar series. 
c and d. Neotoma tenuicauda. Type No. 45,629, 9 • 
Sierra Nevada de Colima, Jalisco, Mexico, 
(x 5.) 
c, upper molar series. 
d, lower molar series. 
[Note.—The accompanying illustrations belong to the U. S. 
Department of Agriculture. They are here used by courtesy of 
Dr. Chas. W. Dabney, Jr., Asst. Secretary of Agriculture.] MERR1AM, THE NEOTOMIN^E.