412 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
From this table we may conclude that — 
1. Cystodiscus Lutz is certainly entitled to separate family rank. 
2. Henneguya Thelohan agrees with Myxobolus in every respect but one, the pres- 
ence of a tail. 
3. Thelohan’s groups, u Myxidiees ” and 11 Chloromyxees ” must undergo rearrange- 
ment (see table below); for clearly Gliloromyxum Miugaz, Mixosoma Thel., and 
Sphcerospora Thel. form a compact group, with which Myxidium has no character of 
consequence in common except the absence of a vacuole. 
4. Sphcemspora and Mixoso ma do not differ at all in the characters given (the 
distinction between these unispeciflc genera resting solely upon the shape of the spore), 
and the two taken together present only a single character in contrast to Gliloro- 
myxum , viz, the number of the capsules. 
5. Geratomyxa agrees sufficiently closely with Gliloromyxum to permit its reference 
to the Cltloromyxidce . 
6. Myxidium must form the type of a separate family. 
The following table shows the relations of Thelohan’s classification to the one 
now proposed : 
Thfilohan’s classification. 
No vacuole, 2 
or 4 c a p- 
sules. 
Group. 
! capsules. ! 
(II. Myxidians.) 
Spores. 
One iodino- 
phile vac- 
uole ; 1 or 2 
capsules. 
Fusiform,! capsule 
at each extremity. 
Myxidium But- 
schli. 
Elongated ; shell, 
formed of 2hollow- 
cone valves sol- 
dered along their 
bases. Gerato- 
myxa Thel. 
Flattened- o v o i d , 
more or less elon- 
gate. Myxosoma 
Thel. 
Spherical. Sphce- 
rospora Thel. 
4 capsules. Chloromyxum 
(III. Chloro- Mingaz. 
myxans.) 
IV. Myxobolans. f Destitute of a tail ; 
capsules 1 or 2. 
Spore-shell. -( 
Myxobolus B ii t- 
sehli . 
With a tail; cap- 
sules 2. Henne- 
guya Thel. 
Proposed classification. 
Genus. 
Family. 
Characters. 
Myxidium Biitschli. 
Myxidiidce 
Bilateral but not antero- 
Geratomyxa Th'61 . . 
• Chloromyxidce. 
posterior symmetry; 
capsules in 2 groups 
rmht and left; no bi- 
valve shell ; no vacuole. 
Bilateral but not antero- 
Chloromyxum Min- 
posterior symmetry; 
gaz, et sub-gen. 
Splicer osyor a. 
capsules in 1 group (at 
the anterior end) ; a bi- 
valve shell, with the 
valve-junction plane per- 
pendicular ( ?) to the Ion- 
Myxobolus BiiTBehli. 
Myxobolidce 
gitudinal plane; no vac- 
uole. 
Bilateral but not antero- 
posterior symmetry; 
capsules in 1 group (at 
the anterior end) ; a bi- 
valve shell rvith the 
val ve-j unction plane 
Cystodiscus Lutz. 
Cystodiscidce . . 
parallel to the longitu- 
dinal plane, an ioaino- 
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. 
