(A K I'M ’LK 10- EXTRACT KI) FROM I'll F W'M.KTIN OF THE U. S FISH COMMISSION 
FOR lhUl. Page* 407 to 4.M.] 
ox THE 
CLASSIFICATION OF THE MYXOSPORIDIA, 
A GROUP OF PROTOZOAN PARASITES INFESTING FISHES. 
HY 
R. R. (UIHLKV, M. IX, 
AH!SI!ST.ANT, l trsT--1 Ii-iI I COMMISSION. 
[Date of publication, July 15, 1893.] 
WASHINGTON: 
GOVERNMENT PRINTING OFFICE. 
1 89 3. (ARTICLE 10 —EXTRACTED FROM THE RFLI-ETIN OF THE U. S. FISH COMMISSION 
FOR 1891. Page* 407 to 420.J 
ON THE 
CLASSIFICATION OF THE MYXOSPORIDIA, 
A GROUP OF PROTOZOAN PARASITES INFESTING FISHES. 
LY 
R. R. GURLEY, \I. D., 
ASSISTANT, U. ST KIHH COMMISSION. 
[Date of publication, July 15, 1803.] 
WASHINGTON: 
GOVERNMENT PRINTING OFFICE. 
1893. 10.—ON run CLASSIFICATION OF THIS MYXOSFORIDIA, A GROUP 
OF PROTOZOAN PARASITES INFESTING FISHES. 
BY R. R. GURLEY, M. I)., 
Assistant, U. S. Fish Commission. 
ITp to the present time very little attention lias been given to the diseases of 
fishes and to their parasites from the standpoint of the effect produced upon the host; 
yet there can be no doubt that a knowledge of such diseases would be of great prac- 
tical value. Anyone who considers the proportions that tisli epidemics sometimes 
attain will hardly be inclined to question the utility of searching investigation in this 
direction. Thus, to take a single instance, Prof. Forbes states* that in the epidemic 
of 18H4 in Lake Mendota it was estimated that fully 300 tons had died. On August 7 
the Madison Transcript reported that 200 tons of fish had been hauled away by the city 
authorities during the four weeks preceding and that the fishes were still dying. Epi- 
demicsof similar extent have been reported in Europe, for several of which (that of the 
barbel certainly, and that of the crayfish probably) tin* Mi/xoxporidia are responsible. 
The important results in the way of prevention of epidemics among domesticated 
animals and cultivated plants, obtained as the result of scientific investigation, afford 
ground for the hope that similar results may he obtained here. <Hiviously the first 
stop in work of this kind is the collection of facts, especially those bearing upon the 
parasite, its nature, life history, intermediate hosts, enemies, and its connection 
(whether causal or otherwise) with diseases or other morbid processes in its host. 
Such data are a necessary preliminary to preventive or curative measures. 
The present paper and a more extended one now in preparation are intended as 
contributions to the objects indicated. In the latter paper the practical bearings of 
the subject will be fully discussed, and all the data as to epidemics of myxosporidi- 
osis will be given. At present it is desired mainly to discuss the classification of the 
subclass Myxonporiiiia Biitschli and to record such genera and species as a study of 
the literature and of such material as was available has led me to recognize. These 
forms will all be fully described and figured in the second paper. The present only 
includes such true .1 f t/.roxporidia as have received or appear entitled to receive binomial 
names, and only such synonymy as is needed for their identification. 
* Hull. II. S. Fish (loin. 1X8X, vm, p. 4S2. 
407 408 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
CLASSIFICATION OF TIIE SUBCLASS. 
The only classification ever proposed is that of Thelohan.* This author enunciates 
three taxonomic principles: 
1. The habitat furnishes no sound basis for specific distinctions, t 
2. The myxosporidium affords no taxonomic criteria. 
3. The spores alone offer (at least in the present state of our knowledge) characters 
suitable to serve as a basis for classification, lie says: 
By noting the differences of form and size of these elements, the number of their polar cap- 
sules, by taking account of the presence or absence of a vacuole in the plasma, of tlieir number in thu 
[panjsporoblastst, one can, I believe, succeed in obtaining elements sufficient for an attempt of this 
kind. 
Thelohan further states that he regards the classification only as a provisional 
one, and that it is the result of a desire to obviate the great confusion arising from the 
habit of designating forms Vfy their habitats. 
The following is Thelohan’s primary classification: 
MYXOSPOltlDIANS. 
Pyriform; capsule 1, at pointed extremity; 
pliile, at large extremity. 
vacuole 1, aniodino- ( 
I. Glugeidian*. 
1 Capsules 2 
II. Myxidians. 
Spores 
No vacuole; capsules 
Form variable 
2 or 4. 
[ Capsules 4 
III. Ohlorovnyxant. 
Vacuole 1, iodinopliile. 
Capsules 1-2 
IV. Myxobolans. 
The three principles mentioned, which form the basis of Thelohan’s classification, 
are unquestionably sound as far as they go, but to obtain a satisfactory arrangement 
it will sometimes be necessary to employ additional characters and to arrange them 
in a different order of rank. Especially will it be necessary in the Fhcenocysten to refer 
constantly to the symmetry and topography of the spore. 
Further, while there can be no question as to the propriety of drawing a sharp 
line between the “Glugeidians” of the above table and the remaining Mt/.vosporidia, 
*Bull. Soc. pliilomat. Paris, 1892, iv, pp. 1(15-178. * 
t While as a general principle this is beyond question, indications are not wanting to show that 
in some cases the seat and, to a somewhat less extent, the host, bear some relations to generic lines. 
One of the most significant facts of organal and zoological distribution is the following: 
Forms. 
Total number 
of specioa. 
Gall and uri- 
nary bladders, 
bile ducts and 
urinary 
tubules. 
Remaining 
organs. 
9 
Very many 
8 
Adplur 2 (3 1) 
i 
All but2(or3). 
t Pansporoblast: The transparent plasma-sphere formed by the condensation of a portion of the 
plasma around one of tin* numerous nuclei of the endoplasm of the myxosporidiuui; in distinction 
from the sporoblasts which result from the segmentation of the pansporoblast. ON THE CLASSIFICATION OF TttE MYXOSPORIDIA. 
409 
the division certainly can not rest upon such a comparatively unimportant character 
as the shape of the spore. I have regarded this division as of ordinal value and 
define the two orders thus: 
I. Cryptocynte» ord. nov. Myxoxporxdxa in which the pansporoblast produces many 
(at the fewest 8) spores; the last minute, without distinct symmetry, with a single 
capsule; type (and only) family, Glugeidw fain. nov. 
Etymology: xpunrog, concealed; xo<mc, capsule. 
II. Pluvnocyntex ord. nov. Myxoxporidia in which the pansporoblast produces few 
(at the most 2) spores;* the last relatively large, with distinct symmetry and 2 or 
more capsules;t type family, Myxobolida: fain. nov. 
Etymology: <pa{»w, I appear; xmme, capsule. 
I CRYPTOCYSTES ord. nov. 
GLUGEID.&! fam. nov 
Qlugeidde* Thrilohan, 1892, Bull. Soc. philomat. Paris, iv, pp. 173-174. 
Definition (provisional as regards negative characters): Cryptocyetex destitute of 
a bivalve shell; with the capsule at the anterior extremity and with an aniodinophile 
vacuole; type genus, Glugea Thelohan. 
This family contains three genera,f " hose relations are shown in the following 
table: 
Myxoaporidium. 
Spores formed in pansporo- 
HMi 
Pansporoblast membrane. 
Genera. 
1 Present 
i Absent 
Inconstant, numerous 
Inconstant, numerous 
Not subporsistent 
Sub|»ersistent 
Qkujea Thf-lohan. 
Pleintojthora gen. nov. 
ThUohania Henneguy. 
GLUGEA Thtflohnn. 1891. 
Cornpt. Reml. liebdom. 8oc. Biol. I'uris, in, p. 29; il>. Tludohan, 1892, Bull. Soc. philom.it. Paris, 
IV, p 174. 
Definition: Glugeida' jmssessinga myxosporidium, and in which the pansporoblast 
produces an inconstant but large number (always more than 8) of spores; pansporo 
blast membrane not subpersistent; type, G.miorospora Thel. (synonym for O.anomttUi 
Moniez). 
Glugea anomala Monies, 1887. 
Nonema anomala, Compt. Rend. Acad. Sci. Paris, civ, p. 1212; Glugea mitroupora, Tlndohan, 1891, 
Compt. Rniul. hebdom. Soc. Biol. Paris, ill, p. 29. 
Glugea destruens Thfdolnm, 1892. 
Bull. Sol', philomat. Paris, iv, pp. 16fi, 174 (footnote). 
* Three asserted in one species (Loydig, Midler’s Archiv., 1851, p. 229). 
t Except (at most) two Myxoboliis species (one of them perhaps inconstantly), which have suffered 
reduction to one. 
tThclohan rroogni7.es only 2 genera, the distinctions between which are mainly based upon 
tin* three characters noted. If (as both he and I he.lieve) these characters are sufficient to determine 
genera at all, a third genus must be recognized, as Pleixtophora typint lit sp. nov. could not (as the above 
table shows) well be forced into either of the existing ones. 410 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
PLEISTOPHORA * gen. nov. 
Definition (provisional as regards negative characters): Glugeidae destitute of a 
myxosporidium and in which the pansporoblast produces an inconstant but large 
number (always more than 8) of spores; pansporoblast membrane.subpersistent (as a 
polysporophorous vesicle); type (and only) species, P. typicalis sp. nov. 
Pleistophora typicalis sp. nov. 
(Corpuscles of Cottus Scorpio Thdlohan, 1890, Annal. de Microgr. Paris, ii, pp. 203, 212; ib. Thtflo- 
han, 1891, Compt. Rend, hebdom. Soc. Biol. Paris, in, pp. 27-8; ib. Henneguy and TluUohan, 
1892, Annal. de Microgr., iv, pp. 618-619, 622, 631, 636.) 
Pansporoblast: Spherical, diameter 15 to 18 p. 
Spore: Ovoid; length 3/*; breadth 1.5 to 2.0 p; chromatophile granules adplur. 4. 
Habitat: Interior of fibrilla* of muscles of Cottus scorpio; diseased mass forming 
white streaks 5 to (» by 3 mm.; not leading to muscle degeneration. 
THELOHANIA Henneguy, 1892. 
In Thdlohan, Bull. Soc. philomat. Paris, iv, p. 174 (footnote); ib. Henneguy and Thdohan, 
1892, Annal. de Miorogr., iv, p. 639. 
Definition (provisional as regards negative characters): Clugeidae destitute of a 
myxosporidium and in which the pansporoblast produces constantly 8 spores; pan- 
sporoblast membrane subpersistent (as an octosporopliorous vesicle); type, T. giardi 
Henneguy.t 
Thelohania contejeani Henneguy, 1892 
In Thdlohan, Bull. Soc. philomat. Paris, iv, p. 174 (footnote). 
Thelohania octospora Henneguy, 1892. 
In Tlidlolian, Bull. Soc. philomat. Paris, iv, p. 174 (footnote). 
Thelohania giardi Henneguy, 1892. 
In Thdohan, Bull. Soc. philomat. Paris, iv, p. 174 (footnote). 
Thelohania macrocystis sp. nov. 
(Sarcosporidiau of Paler,monetes variam Garbini, 1891, Atti Beale Accad. Lined Roma, vii, 
Sem. 1, pp. 151-152, with figs.; myxosporidian of ibid. Thdlolian and Henneguy, 1892, 
Compt. Rond, hebdom. Soc. Biol. Paris, iv, p. 586). 
Sporophorous vesicle (subpersistent pansporoblast) elongate-fusiform. 
Habitat: Muscles of PaUcmonetcs variam from the Mincio, near Verona. 
II. PHiENOCYSTES ord. nov. 
It is in the classification of this order that the criteria furnished by Thdlohan most 
need to be supplemented by considerations drawn from the symmetry of the spore. 
Considering the taxonomic importance of symmetry throughout the animal kingdom, 
it is strange that no attention has yet been paid to it in the Myxosporidia. But a 
little study of it shows that, whereas in all fusiform spores the pointed extremities 
have heretofore been loosely lumped together as “ends,” those of Myxidium lieber 
k'uhnii Biitschli are not ends (sens 8trict.m, = anterior and posterior), but sides; for the 
* Etymology: nXelnroq, very many; iptpeiv, to carry, 
tl propose T. giardi Henneguy as the type of the genus. ON THE CLASSIFICATION OF THE MVXOSl'OUIOIA. 
411 
sport* is symmetrical on cither (right or left) side of the vertical plane,* but it is asym 
metric oil cither (anterior ami posterior) side of the transverse plane. On the other 
hand, if, as set*ms probable, the generic reference of C.! diploxyx sp. nov. be correct, then 
“ends” in Oystodiseus are ends, properly speaking. It. is needless to emphasize the 
taxonomic import of these results, for we are thus enabled to orient the spore and the 
results of such orientation may be summed up as follows: 
1. Within this order the most important characters are the position anti grouping of 
theca psules. Compared to this the mere number of these bodies is a character of minor 
importance; for not only lias Mgxobolnx 1 or 2 and Gyxtodixcntt 1! or 4, but the number 
even varies in the same species, Myxidium lieberkiihnii BUtschli having 2 or d.t 
But whether 1 to 2 or 1i to 4, the topographic relations are never varied. Thus in 
Myxobolus they are always in one group at the anterior end; in Cyxtodixcus in two 
groups, anterior and posterior; and in Myxidium in 2 groups, right and left. 
Similar results are obtained with relation to the position of the valves, or, mother 
words, to the orientation of their plane of junction. 
The following table shows the relations of these points to generic lines: 
Comparison of generic characters in the Vhanocystes. 
[ X =: present; 0 absent; ( ) :lesa usual; not known.] 
Symmetry. 
Capsules. 
Shell. 
Vac- 
uole. 
Tail. 
Antero- 
poste- 
rior. 
Bilat- 
eral ; 
perfect. 
Number. 
In one 
group 
(at the 
anterior 
eml.) 
In two groups. 
Bi- 
valve. 
Inclination of 
plane of junc- 
tion of valves 
to longitudinal 
plane. 
At the 
(antcrior 
aml pos- 
terior) 
ends. 
In tlie 
(right 
and left) 
wings. 
0°. 
90°. 
X 
x 
X 
X 
x 
o 
u 
x 
2 (or 1) 
X 
X 
x 
o 
u 
X 
2 
X 
X 
x 
u 
4 
X 
x 
(?) 
o 
o 
0 
x 
2 
X 
o 
o 
Sjihirruxiiora Tlieloliuu 
0 
X 
2 
X 
X 
— 
_ 
0 
0 
0 
(') 
') 
X 
x 
o 
o 
0 
x 
2 (or 4) 
x 
0 
o 
0 
'Imperfect. Shetland capsules symmetrical: sporoplasm unilateral. 
1 From analogy and general similarity of appearance, this genus can hardly be other than bivalve. 
*Thethree pianos to which symmetry may ho referred may be thus defined: 
Vertical plane: Median, longitudinal and intereapsular in position. 
Transverse plane: Vertical, transverse and (in Mytolt tins) postcapsular in position. 
Lo.igitudinal plane: Horizontal, longitudinal and per capsular in position. 
* Dalbiaui, 1HH3, Journ. do Microgr. l'aris, vu, p. -74, tig. 64 g. 412 
HULLETIN OF THE UNITED STATES FISH COMMISSION. 
From this table we may conclude that— 
1. Gystodiscus Lutz is certainly entitled to separate family rank. 
2. Henneguya Thelohau agrees with Myxobolus in every respect but one, the pres- 
ence of a tail. 
3. Thelohan’s groups, “ Myxidiees” and “ Ghloromyxeesv must undergo rearrange 
ment (see table below); for clearly Ghloromyxuin Miugaz, Mixosomn Thel., and 
Sph(cro8j)ora Thel. form a compact group, with which Myxidium, has no character of 
consequence in common except the absence of a vacuole. 
4. Sphcerospora and Mixosomn do not differ at all in the characters given (the 
distinction between these uuispecific genera resting solely upon the shape of the spore), 
and the two taken together present only a single character in contrast to Ghloro 
myxum, viz, the number of the capsules. 
5. Ceratomyxa agrees sufficiently closely with Ghloromyxum to permit its reference 
to the Ghloromyxidce. 
(5. Myxidium must form the type of a separate family. 
The following table shows the relations of Thelohan’s classification to the one 
now proposed: 
Th61ohan’s classification. 
Proposed classification. 
Group. 
Genus. 
Family. 
Characters. 
No vacuole, 2 
2 capsules. 
"Fusiform,! capsule 
.1/yxidi u m I »ii tsclil i. 
Myxidiidie 
Bilateral but not antero- 
or 4 c a p- 
(11. Myxidians.) 
ateacli extremity. 
posterior s v m m etrv; 
sules. 
Maxi ilium Hut- 
sciili. 
capsules in 2 groups 
right and left; no bi- 
valve shell; no vacuole. 
Elongated; shell, 
Ceratomyxa Thel .. 
Spores. ■ 
formed of 2 hollow- 
cone valves sol- 
dered along their 
bases. Geratu- 
myxa Tliel. 
Flattened-o void, 
• 
more or less cion- 
gate. Myxogoma 
• ('hloromyxidce. 
Bilateral but not antero- 
Thel. 
Chloromyxum Min- 
posterior symmetry; 
Spherical. Sph.ce- 
gaz, et sub-gen. 
capsules in 1 group (at 
ronpora Thel. 
Sphieronpora. 
the anterior end); a bi- 
valve shell, w i t h the 
4 capsules. 
Oh lor o my xum 
valve-junction plane per- 
pendicular (1) to the Ion- 
(111. Chloro- 
Mingaz. 
liiyxaiiH.) 
gitudinal plane; no vac- 
uole. 
One iodino- 
IV. Myxobolans. 
f Destitute of a tail; 
pliile vac- 
capsules 1 or 2. 
f 
uole; 1 or 2 
Myxoboluk B ii t- 
capsules. 
tS pore-shell. 
sclili. 
,Myxobolun Biitschli. 
Myxobolidce 
Bilateral but not antero- 
With a tail; cap- 
posterior symmetry; 
sules 2. llenne- 
capsules in 1 group (at 
( guya Tliel. 
the anterior end); a bi- 
valve shell with the 
valve-junction p lane 
parallel to the longitu- 
dinal plane, an iodino- 
Gyntoilincun Lutz. 
Gyntodiscidae .. 
phile vacuole. 
Bilateral and antero-pos- 
terior symmetry; cap- 
sules in 2 groups, ante- 
rior and posterior; a bi- 
valve shell with the valve- 
’ junction plane perpen- 
dicular to the longitudi- 
nal plane; condition of 
sporoplasm unknown. »»N THE CLASSIFICATION OF THE MYXOSPOB1D1A. 
413 
As a result of this analysis, the order I’luvnocyntcn may be divided into tin: follow- 
ing families: 
CYSTODISCID.® fam. nov. 
Definition: Pfucnocynten whose spores )H>ssess antero jMjsterior and bilateral sym- 
metry; capsules in 12 groups, situated at the (anterior and posterior) ends; a bivalve 
shell, the plane of junction of whose valves is perpendicular to the longitudinal plane: 
condition of sporoplasm* unknown; type (and only) genus Cystodiscw+hutz. 
CYSTODISCUS Lutz, 1889. 
Centralhl. f. Makt. u. Parasitenkde., v, p. 88. 
Definition: Characters those of the family; type, C. inline mux But/. 
Cystodiscus iinmersus Lutz, 1889. 
Coutralbl. f. Makt. u. Parasitenkde., v, pp. 81-88; tigs, separately and subsequently. 
Cystodiscus ? diploxys sp. nov. 
(Psornspcrms of 1’yralix oiridana Malbiaui 1867, Journ. Anat. et Physiol. Paris, p. 335 (foot- 
note), t. 12, f. 10-12.) 
Spore: Parallel sided fusiform; ends symmetrically double convex-curved pointed; 
plane of junction of valves coincident with the vertical plane; capsules - at each end, 
of equal size. 
Habitat: Tortrix viridana. 
M YXOHOLID2E fain. nov. 
(Myxotpuridieai Perugia, 1891, Moll. Scientif. Pavia, xm, p. 23; “ Myxobnlrios”Th61ohaii, 1892, 
Hull. Hoc. philomat. Paris, iv, pp. 173, 176.) 
Definition: riuvnocj/xtcx whoso spores are destitute of antero posterior, but pos 
sews bilateral, symmetry;J capsules in 1 group at the anterior end; a bivalve shell, the 
plane of junction of whose valve is parallel to the longitudinal plane; an iodiuophile 
vacuole; type (and only) genus, Myxobolux Biitscldi. 
MYXOBOLUS Biitschli, 1882. 
Hronn’s Thicr-ltoich, I, t. 38, f. *►—10; Myxoxporidium $ Perugia, 185)1, Doll. Scioutif. l'avia, xm, 
p. li.'l; Myxobol ax ot .\fycoaporidium Weltner, 1892, Sitzgsber. d. (Josollsch. Natnrf. Freuudc 
Merlin, pp. 31-35; Myxobolim tit Thclohan, 1892, Hull. Hoc. pliilouint. Paris, iv, 
pp. 176, 177. 
Definition: Characters those of the family; type M.mullcri Biitschli. 
• Sporoplanm. Protoplasm of the spore. 
♦ 1 propose Mifxooporidiuin Perugia (synonym for Afyxoholux Hiitsclili) as the type genus of the Fam. 
Myxoxporidieat Perugia. 
(Except species which have snllored reduction of characters (Myxobolux nnicapxulalnx sp. nov., .)/. 
pirijormix 1 liel.). 
t I propose M. merlucii Per. as the type species of this genus. 
|| I propose //. pxoruM per mica Th61. as tin* generic type. No valid generic distinction seems possi- 
ble between the untailed and the tailed forms, for which latter Thclohan proposed Ucnneynya. Apart 
from the absence or presence of a tail (both of which conditions may, according to good observers, 
occur in the same species; cf. Woltuer, Sit/.gsbcr. ties. Natnrf. Freuude Berlin, 1892, pp. 28-38) the 
only character relied upon for their separation is the constancy of 2 capsules in the tailed forms, but 
this is also the typical number for Myxobolux and the presence of two exceptional species docs not 
militate against the rule. 414 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
Myxobolus unicapsulatus sp. uov. 
(Psorosporm of Labeo nilotiom Miiller, Miiller’s Arcliiv., 1841, p. 487, t. 16, f. 5 a-d.) 
iSpore: Of the form and size of Ghloromyxum dujardini Thel.; eapsule only 1, 
obliquely directed. 
Habitat: Labeo nilotiom, from the Nile. 
Myxobolus piriformis Thclolian, 1892. 
Bull. Soc. pliilomat. Ihiris, iv, p. 177. 
Myxobolus inequalis sp. nov. 
(Psorosperms of Pimelodm blochii (Valenc.) Miiller, Miiller\s Archiv., 1841, p.487, t. 16, f. 6 <i. b \ 
iSpore: Length 11 q; breadth, 7 /r; capsules 2 of unequal size. 
Habitat: On Pimelodm clarias Bloch (=Silurus olarias Valenc.), from Guiana 
and Surinam. 
Myxobolus mugilis Perugia, 1891. 
Myxosporidium muyilis, Boll. Scioutif. Pavia, xm, pp. 29-4; M yxobolus muyilis Thtdolian, 1892, 
Bull. Soc. pliilomat. Paris, iv, p. 166. 
Myxobolus oviformis Theloban, 1892. 
Bull. Soc. pliilomat. Paris, iv, p. 177. 
Myxobolus miilleri Biitsclili, 1882. 
Bromi’s Thier-Kcicli, i, t. 88, f. 6-10. 
Myxobolus oblongus sp. uov. 
(Psorospcrms of Catostomm tub ere nl atm Miiller, Miiller’s Arcliiv., 1841, pp. 487-90,1.16, f. 7-9.) 
Cyst: Round or elliptic, l mm. or less. 
Spore: Spatular or roundoblong; length, L4 to 17 <; greatest breadth and 
greatest thickness at about the junction of the anterior and second fourth of the 
length; breadth, 8.5 yu; thickness, 5 to 0 a; width of ridge nearly equal to one-third 
of thickness; capsules, 2; nuclei 2, and perhaps* more; vacuole not seen. 
Habitat: Subcutaneous on head of Erimyzon sueetta Lac. (= Catostomus tuber- 
culatus Le Sueur). 
Myxobolus ellipsoides Tlidlohan, 1892. 
Bull. Soc. pliilomat. Paris, iv, p. 177. 
Myxobolus bicostatus sp. nov. 
(Myxosporidian sporcof branchia; of Tinea rulyaris Biitsclili, 1882; Bronu’s Thier-Rcich, i, t. 
* 38, f. 19.) 
Spore: Shell with 2 oblique ribs over the longitudinal axes of the capsules; cap- 
sular index 0.50. t 
Habitat: Branchiae of Tinea tinea L. 
Myxobolus lintoni sp. nov. 
(Psorosperms of Cyprinodon varieyatus Linton, 1891, Bull. U S. Fish Com. for 1889, ix, pp. 
99-102, t. 35, f. 1-16.) 
Spore: Ovate; length, 13.0 yu; breadth, 11 yu; thickness about 8 yu; shell, valves 
separating rapidly in sulphuric acid (cold, concentrated); capsules, 2, equal; lila- 
ments extruded under influence of sulphuric acid and of iodine water; nuclei ad i>lur. 
4, 2 of which are the pericornual; f vacuole present. 
* The condition of the material being such as not to exclude the possibility of sporoplasuiic 
degeneration, these results arc not entirely decisive. 
t Capsular index. The ratio of the length of the capsule to the antero-posterior diameter of the 
shell cavity. 
i Pericornual nuclei. The 2 nuclei ( “ granules ’’ “globules” ) situated at the autero-lateral angles 
sCornua) of the sporopla.s u or ou the posterior extremities of the capsules. ON THE CLASSIFICATION OF THE MVXU8POK1DIA. 
415 
Habitat: Subcutaneous, on Cyprinodon varicyatut, from the Atlantic at Woods 
I loll, Mass., August 20, 1889. 
MyxoboluH obesus, up. nov. 
(Psorospenii of tlio “ Ablett®,” Halbiani, 1NK3, Journ de Microgr., vii, p. 203, tin- 43.) 
•Spore: Very broadly ovate. 
Habitat: On Alburnus alburhuh L. 
Myxobolus cycloides, sp. nor. 
(PsorosperuiH of Cyprinntr rutiluh (pure) Muller, Midler’s Arehiv., 1S41, pp. 4K1, 4S0, t. 16, f. I 
. d-y.) 
Spore: Subcircular-ovate to broadly rounded elliptic. 
Habitat: Opercle and pscudobranchiu* of Ixudecun rntilun L., fromGerman livers, 
May and June. 
Myxobolus splieralis up. nov. 
(Psorosperins of Coretjonut fera (’laparede, 1S74,in Limel's Hint. Nat.d. Poissons tin luissin du 
Ionian, (iencvu, pp. 113-4.) 
Spore: Uutailed; perfectly spherical; diameter,!)//; containing a single spherical 
very strongly refringent “nucleus” [1 vacuole]. 
Habitat: Cysts imbedded by thousands in the branchial mucosa of ('oregonun 
fern Jur. 
Myxobolus globosuB, ep. now 
Cyst: Elongate-elliptic or rod-shaped; length nil max., 0.50 mm. 
Spore: Globose; length, 7 or 8 //; breadth, (J //; thickness, 5 //; ridge very wide 
one-third of thickness; capsular index somewhat more than 0.50. 
Habitat: liranchial lamelhe of Erimyzon sucetta Lac. (= Catontomm tuberculatux 
Le Sueur), from Kinston, N. C., Columbia, S. C., and from the tributaries of the Fox 
River, Miss, (collections U. S. National Museum). 
Myxobolus traiiBOvalis, sp. now 
Spore: Transversely elliptic; length, usually 0, occasionally 7 //; breadth, 8/i; 
valves separating in sulphuric acid; ridge narrow; capsules 2, equal; capsular index, 
0.50; tilaments extruded under the influence of glycerine and of sulphuric acid; nuclei, 
2, rarely only 1, pericornual nuclei apparently absent; vacuole probably present. 
Habitat: In hollow of under surface of scales of Phoxinu* fund ulo idee from Four 
mile Run (tributary of Potomac River), Carlins, Va., June 29, 1892. 
Myxobolus merlucii l’erugia, 1891. 
Myxoxporidium merlucii, Boll. Solentif. Pavia, xm, pp. 22, 24. f. 9-14. 
Myxobolus perlatus, sp. nov. 
(Psorosperins of Acer inn ctrnua Halbiuni, 1SS3, Journ. de Microgr. Paris, vii, pp. 201, 204, tig. 
44.) 
Spore: Wider than long. 
Habitat: On (lymnocephaluft cornua L. 416 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
Myxobolus?? zscliokkei, sp. nov.* 
(Psorosperins of Coregonus fera Zschokke, 1884, Archiv. de Biol, v, pp. 234-5, t. 10, f. 16.) 
Cyst: Oval, pea to nut size; multiple (up to 30). 
Spore: Body lenticular or oval, a little wider in front than behind; often bearing 
in front a blunt prolongation; posteriorly one distinguishes two “toils” (queues) 0 to 8 
times longer than the body, attenuating posteriorly, curved and undulating; the num- 
ber of two “tails” is constant; at the pole opposite to the “ tails ” are 2 oval, trans- 
parent anteriorly converging vesicles; one sometimes sees, however, an extremely tine 
canal extending from the posterior end of each vesicle to the base of the corresponding 
“ tail”; the vesicles then probably play here also the role of receptacles for the “ tails”; 
round retractile globules are also seen at the bases of the vesieles; the remainder of the 
body is tilled by a homogeneous plasinic mass which frequently contracts to the center 
of the body cavity, forming a clearly distinct round or oval mass. 
I Labitat: Subcutaneous and superficial intermuscular tissue of Coregonus fera 3 ur.; 
April and May. 
Myxobolus brevis Thtfiohan, 1892. 
Uenneguya brevis, Bull. Soc. philoruat. Paris, iv, p. 177. 
Myxobolus medius Th61ohan, 1892. 
Uenneguya media Bull. Soc. philomat. Paris, iv, p. 176. 
Myxobolus monurus, sp. nov. 
(Psorosperms of Aphredoderus sayanus Ryder, 1880, Amer. Nat,, xiv, pp. 211—21*2, tigs. 1, 2.) 
Cyst: Lenticular, large, about 20 in number. 
Spore: Tailed; body lenticular or slightly obovate; tail undivided, thick at origin, 
gradually attenuating, more or less curved, 2 to 3 times as long as body; capsules 2, 
equal, subparallel. 
Habitat: Subcutaneous intermuscular tissue of A. sayanus from near Woodbury, 
N. J. 
Myxobolus macrurus, sp. nov. 
Cyst: 15 to 20 or more, the size of a pinhead. 
Spore: Plainly dorso-ventrally asymmetric; tailed; body round-elliptic; 10 or 11 
/u long; 0 to 8 yu broad; 1 yu thick. Shell insoluble in sulphuric acid (cold, concen- 
trated); superior valve more convex than inferior; tail somewhat less transparent than 
shell, completely dissolved by cold concentrated sulphuric acid; almost or entirely in- 
visible in balsam; length 30 to 40 /v, usually much less, the attenuate posterior portion 
being easily, and consequently frequently, broken otf; tail separated entirely from 
shell by iodine water. Capsules 2, equal; nuclei ad pi ur. 4, 2 of them being the peri- 
cornual ; vacuole present. 
Habitat: Cysts invariablyt embedded in the subcutaneous tissue of some part of 
the head (especially the under surface of the lower jaw) of Jlybognathus nuchalis Ag., 
from the Neelies liiver, 14 miles east of Palestine, Texas, November 24, 1801. 
* Dedicated to Dr. F. Zscliokke, of Basel. 
t Amoug several hundred cysts, one was seen at the base of the pectoral lin, say 3 nun. behind 
the head. ON THE CLASSIFICATION OF THE MYXOSl’OUIDIA. 
417 
MyxoboluB strongyluruB, Bp. iiov. 
(pHoroHp'-riiiH of SfjiKxlontiM mcIhiJ, Mii 1 lor, Miillcr’H Archiv., 1811, pp. 480-481, t. 16, f. 2.) 
Spore: Body anteriorly blunter than in M. sckizurus; length of body 0 ft; breadtli 
5.4 ft; tail single, undivided, very ]>eculiar in being constantly oblique in the longi 
tudinal plane. 
Habitat: Encysted in skin of head of H.schal from the Nile. 
MyxoboluB kolesnikovi, “ Hp. nov. 
(I’HoronpcrniH of Cvregonus /era Kolomiikoff, 1886, Veter. Vcntnik Kli:irkolf.,v, pp. 242-248, f. 1-3.; 
Cysts: Numerous (up to HO), spherical or oval, 10 to HO mm. long by 7 to -0 mm. 
broad. 
Spore: Round or oval with a sharp anterior end; tail single or double, thick at 
its origin, attenuating gradually. 
Habitat: Interstitial connective tissue of the thoracic muscles of (Jorcyonu* /era 
•fur. 
KolesnikotF’s tigures show the “double” tail to be merely the separated (lat 
erally shifted) halves of the really single tail. To this species should probably be 
approximated one of Claparede’s 3 forms, t viz, the tailed form habitant in the muscles 
of C. /era. 
Myxobolus linearis, np. nov. 
(PuorosperuiB of Pimelodut tebce and of Platgxtoma fanoint um MUllor, Miiller’H Archiv., 1841, p. 
489, t. 16, f. 10). 
Spore: Body lanceolate-linear; length 3 to 4 times breadth; capsules 2, equal, 
entirely parallel-appressed; tail single, occasionally double. 
Habitat: Cysts in membrane lining branchial cavity of Rkamdia sabic Cuv. & Val., 
and in branchial lamellm of I’aeudoplatyHtoma fan datum L., both from South American 
rivers. 
In cysts at the base of the dorsal tin of Ameturux mclas Kaf., from Storm Lake, 
Iowa, a spore occurs which I strongly suspect to be identical with this species, as it 
answers in every respect to the above (rather meager) diagnosis. It is peculiarly 
interesting, as the tail is composed of a dorsal and a ventral half, and is insoluble in 
sulphuric acid (cf. M. macrurus). 
MyxoboluB schizuruB. Bp. nov. 
(Psoro«iK3rm8 of Ehox lucin* Miiller, Miiller’H Archiv., 1811, pp. 477-478, t. ll», f. 1.) 
Cyst: 0.44 to 1.00 min. in diameter. 
Spore: Body oval, length 12 pi; breadth 0 pi; thickness one-half the breadth; tail 
stout at origin, 3 to 4 times length of body, very frequently (probably as a rule) more 
or less bifurcate; capsules 2, equal, diverging posteriorly. 
Habitat: In cellular tissue of the eye muscles, in that of the sclerotic, and in that 
between the sclerotic and choroid of Esox Indus in May and June. Miiller failed to find 
it in North American pikes. 
* Dedicated to N. F. KoloHiiikoft', who first figured this form. 
tClaparode in LuiioI’h Hist. Nat. d. l’oisaooa ilu bass in du Leman, pp. 113. 418 
BULLETIN OF TIIE UNITED STATES FISH COMMISSION. 
Myxobolus crepliui, * sp. nov. 
(Psoroaperms of Acerina vulgaris Creplin., 1842, Wiegm. Archiv. f. Naturgeseh, i, pp. 61-63, t. 1, 
f. 1 a-e; cf. Weltner, 1892, Sitzungs.-Ber. Ues. Naturf. Freunde Berlin, pp. 29-31, 34). 
Spore: Body elongate ventricose-elliptic; length 17.3 /<; breadth 5.8 /i; tail simple, 
as long as or a little longer than the body; capsules 2, equal. 
Habitat: On Gymnocephalus cernua L., collected March 14,1837. 
Weltner believes the form observed by him in the ovary of Esox luciutt to be iden- 
tical with this form. Weltner’s species was sometimes tailed and sometimes untailed. 
Myxobolus psorospermica Thdlohan, 1892. 
Henneguya psorospermica, Bull. Soc. philomat. Paris, iv, pp. 167, 176. 
Myxobolus diplurus, sp. nov. 
(Psoroaperms of kidney of Lota vulgaris Biitsclili, 1882, Bronu’s Thier-Reieh, i, t. 38, f. 21.) 
Description (from figure). 
Spore: Capsules 2, equal, posteriorly situated; tail double from base, the 2 halves 
adnate. 
Habitat: Kidney of Lota lota L. 
CHLOROMYXIDiE fain. nov. 
(“ Chloromyxdes ” et “Myxidides” (pars) Thdlohau, 1892, Bull. Soc. philomat. Paris, iv, pp. 
173, 176.) 
Definition: Pluvnocystes destitute of antero posterior, but possessing bilateral, 
symmetry;t capsules in 1 group at the anterior end; a bivalve shell, the plane of 
junction of whose valves is perpendicular (?) to the longitudinal; no vacuole; type 
genus Chloromyxum Ming. 
CHLOROMYXUM Mingazzini, 1890. 
Bull. Soc. Nat. Napoli, IV, p. 160; ib.t Spharospora, Myxosoma et Mixosoma f Thdlohan, 1892, 
Bull. Soc. philoinat. Paris, iv, pp. 173, 175-6. 
Definition: Ghloromyxidcc with subspherical or ovate spores, whose breadth does 
not exceed their length; valves hemispherical; sporoplasm bilaterally and symmet- 
rically situated; type G. leydigii. 
Chloromyxum sens, strict. 
Definition: Quadricapsulate Chloromyxa; type G. leydigii. 
Chloromyxum fluviatile Thdlohan, 1892. 
Bull. Soc. philomat. Paris, iv, pp. 173, 176, fig. 2. 
* Dedicated to the discoverer, J. C. L. Crepliu. 
t Imperfect from unilateral position of sporoplasm in Ceratomyxa. 
(See subgenus Spharospora, p. 419. The table on p. 411 shows that Spharospora and Mixosoma 
differ from Chloromyxum by only a single character, viz: the number of the capsules. As shown on p. 
411, this character is a subordinate one compared to the grouping and position of the capsules, in 
which latter all the three genera agree. They may, therefore, all be grouped under one genus. 
The two unispecific genera Spharospora and Mixosoma have (at least as far as the record now 
shows) absolutely no distinctive character but the shape ofthespore. They arc therefore fused. Provi- 
sionally (but with some hesitation) I have recognized Spharospora (including Mixosoma) as a sub- 
genus. Its sole claim to such distinction rests on 2 capsules as against 4 in Chloromyxum proper. It 
is also worthy of note that the possibility of transitions are by this definition arbitrarily excluded, 
inasmuch as all our experience shows that increase of capsule number is by duplication and not by 
addition. So that the possibility of its ultimate entire fusion with Chloromyxum seems by uo means 
remote. ON THE PI ASSIFIPATION OF THE MVX08PORIDIA. 
419 
Chloromyxum mucronatum sp. nov. 
(Psorosperms of (iadue tola Licberkiihn, Muller’s Archiv., 1851, pp. 352-3, 368, t. 14, f. 5,6.) 
Myxosjxtridium: Measuring 75 // or less; spherical or ellipsoidal, rarely irregular. 
Spore: Broadly rounded-oval; concave pointed anteriorly; length ad max., 8 i. 
Habitat: Free in urinary bladder of Lota lota L. 
Chloromyxum leydigii Mingaz., 1890. 
Holl. Soc. Nat. Napoli., iv, jq>. 160—1 (see also the next species). 
Chloromyxum incisum sp. nov. 
(Psorosperms of Raja hatia Ley dig, MUller’s Archiv., 1851, pp. 225-226, 234. t.8, f. In-/.) 
Myxosporidium: Biliary yellow, roundish or somewhat elongate, 29 to 88 in 
diameter, without or with 1 to 1 pansporoblasts. 
Sport*: Sharply euneate-oval,posterior bonier radiate-indued, resembling a radiate- 
ribbed Lamellibranch shell. 
Habitat: Free in gall-bladder of Raja batix L. 
In face of the striking difference between this spore form and G. leydigii, the 
present evidence (which consists of Mingazzini’s opinion* without any detailed evi 
deuce, Perugia’s opinion,t too little explicit, and the probably not independent opinion 
of Thelohan $) is insufficient to warrant the fusion of the two forms, especially as it 
does not appear that either Mingazzini or Perugia examined the gall-bladder of 
Raja hatix. 
Chloromyxum ? ? congri Perugia, 1891. 
Afyxoaporidium congri. Holl. Hcientif. Pavia, xm, pp. 24-5, f. 15-20. 
Habitat: Gall-bladder of Leptocephalux conger collected in August, 1890. 
Subgenus 8imi.*:rosi>ora Thfdohan, 1892. 
Hull. Soc. philomat. Paris, iv, p. 175; el Myxoaoma ibid., p. 175. 
Definition: Bicapsulate Chloromyxa; type Ch loromy.ru >n (*V.) elegans Tied. 
Chloromyxum elegans 1892. 
Upkerroapora elegant, Hull. Sue. philomat. Paris, iv, pp. 167, 175. 
Chloromyxum dujardini TlnHohnn, 1892. 
(Psurosperms of Cyprinna nttilux (part) Muller, Muller's Archiv., 1811, pp. 481, 486,1.16, f. 4 b, c; 
psorosperm of Cyprinua tryihrophtUatmua Dnjnrdin, 1845, llist. Nat. des Heliuiuthes, p. 
644, t. 12, f. 12 N„ 12 N,.) 
\fixoaoma dujardini, Hull. Soc. philoniat. Paris, iv, p. 175. 
Myxosporitlium : 1.36 to 1.50 mm. loop. 
Spore: Ovate, pointed anteriorly, broadly rounded posteriorly; length 10 to 12 /r; 
eapsules 2, of equal size. 
Habitat: Branchial lamella4 of Leueixeux (Ncardiuiux) erythrophthalmux from the 
Vilaino, at Kcnnes, France; pseudobranehia* of Leueixeux rut Huh, from German rivers. 
Concerning tlie form observed by him, Muller says: 
Once there was found on the pseudnbrnnohi.e (Xehenkicmen) a mass of small yellow cysts. The 
size of this mass was I lines. This time all the cysts contained elongate capsules with pointed ante- 
rior and bluntly rounded posterior ends (f. 4 /*). On the Hat border the convex surfaces were exactly 
equal and the two diverging vesicles were attached interiorly at their points. 
* Boll. Hoc. Nat, Napoli, 1890, iv, pp. 160-161. 
t Boll. Bcientif. I “avia, 1890, xii, p. 138. 
{ Bull. Sue. philomut. Paris, 1892, iv, p. 176. 
$ Type Chloromyxum (Mixoaoma) dujardini. 420 
BULLETIN OP THE UNITED STATES PISH COMMISSION. 
Thus this form was never found coexisting in the same cyst with Myxobolus 
cycloides sp. nov. Considering the great frequency of occurrence of the latter species 
such coexistence would be expected if they were merely different forms of one species. 
Their persistent non-association thus strongly reenforces the argument in favor of 
their specific distinctness, drawn from their different characters. 
The synonymy is on the authority of Thelohan (letter to the author, 1893). He 
has found Mixosoma dujardini upon both of the fishes named above and believes that 
Mfiller’s and Dujardin’s figures represent the same species. 
CERATOMYXA Tlidlohan, 1892. 
Bull. Soc. philomat. Paris, iv, pp. 169, 175. 
Definition (provisional): Chloromyxidm with bilaterally symmetrical, transversely 
extended, sub-isosceles-triangular spores, whose breadth greatly exceeds the length; 
valves hollow-conical with solid tips; sporoplasm unilaterally and asymmetrically 
situated; type G. sphccntlosa Tliel. 
Ceratomyxa sphaerulosa Thtflohan, 1892. 
Bull. Soc. philomat.- Paris, iv, pp. 171-3, 175, fig. 1. 
MYXIDIID-ffi fain. nov. 
(“ ” (pars) Tlufiohan, 1892, Bull. Soc. philomat. Paris, iv, pp. 173, 175.) 
Definition (provisional, as regards negative characters): Phcenocystes destitute of 
an tero-posterior, but possessing bilateral symmetry; capsules in 2 groups in the (right 
and left) wings; no bivalve shell; no vacuole; type (andonly) genus Myxidium Biitschli. 
MYXIDIUM Biitschli, 1882. 
Bronn’s Thier-Reich, I, t. 38. 
Definition: Characters those of the family; type M. lieberkiihnii Biitschli. 
Myxidium lieberkiihnii Biitschli, 1882. 
Bronn’s Thier-Reicli, i, t. 38, f. 12-15. 
Probably a second species is Leydig’s “ psorosperm ” of the bile-ducts of Raja 
batis, Muller’s Archiv, 1851, pp. 220, 234, t. 8, f. Ay.