420 
BULLETIN OF THE UNITED STATES FISH 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 
Muller’s and Dujardin’s figures represent the same species. 
CEKATOMYXA TMlohan, 1892. 
Bull. Soc. philomat. Paris, iv, pp. 169, 175. 
Definition (provisional) : Chloromyxidce 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 C. sphcerulosa Thel. 
Ceratomyxa sphserulosa Th61ohan, 1892. 
Bull. Soc. philomat. Paris, iv, pp. 171-3, 175, fig. 1. 
MYXIDIIDiE fam. nov. 
(“Myxidiees” (par*) Thdlohan, 1892, Bull. Soc. philomat. Paris, iv, pp. 173, 175.) 
Definition (provisional, as regards negative characters) : Pluenocystes destitute of 
antero-posterior, but possessing bilateral symmetry; capsules in 2 groups in the (right 
and left) wings; no bivalve shell; no vacuole; type (and only) genus Myxidium Biitschli. 
MYXIDIUM Biitschli, 1882. 
Bronn’s Tliier-Reich, I, t. 38. 
Definition: Characters those of the family; type M. lieberlciihnii Biitschli. 
Myxidium lieberkiihnii Biitschli, 1882. 
Bronn’s Tliier-Reich, i, t. 38, f. 12-15. 
Probably a second species is Leydig’s “ psorosperm ” of the bile-ducts of Baja 
batis, Miiller’s Arcliiv, 1851, pp. 226, 234, t. 8, f. 4 g. 
