THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. 277 
87. Ceratomyxa sphzrulosa Thélohan, 1892. Pl. 41, fig. 4. 
Bull. Soc. philomat. Paris, Iv, pp. 171-3, 175, fig. 1; ib. Thélohan, 1892, Compt. 
Rend. Acad. Sci. Paris, cxv, pp. 961-2; ib. Gurley, 1893, Bull. U. S. Fish Com. 
for 1891, x1, p. 420; ib. Braun, 1893, Centralbl. f. Bakt. u. Parasitenkde, xiv, 
pp. 738-9; ib. Braun, 1894, Centralbl. f. Bakt. u. Parasitenkde, xv, p. 87. 
Cyst, none. 
Myxosporidium.—Spheriecal or ovoid; youngest stages exhibiting very 
distinct amceboid movements, colorless; older individuals yellowish, 
presenting a very remarkable constitution. Ectoplasm thin, emitting 
lobed pseudopodia, with very slow movements. Endoplasm appearing 
riddted with small (3 or 4 yz) clear spheres between which lies a gray- 
ish, finely granular plasma. Spheres often exhibiting, grouped at their 
center, a variable number (most frequently 5 or 6) of small yellow, brown, 
or greenish granules which resist nitric acid and potassium hydrate 
longer than the spheres which envelop them. Thélohan was unable to 
express any opinion as to the nature of the spheres, which, he remarks, 
constitute one of the most remarkable peculiarities of this species. 
Spore formation.—Each myxosporidium forms at the most 2 spores; 
never more. Solid distal portion of valve folded back along the pos- 
terior border during development. Thélohan notes the similarity in this 
respect to the development in the tailed Myxrobolus species (see p. 248) 
and says that the anterior convexity of the curve presented by the long 
(transverse) axis seems the effect of this primitive arrangement. 
Spore.—Transversely extended, symmetrically (or subsymmetrically) 
double scalene-triangular; length, 8 to 10 or 12 4; breadth, 90 to 100 yw. 
Shell bivalve; valves right and left; symmetrical or subsymmetrical ; 
shape of each valve hollow-conical, with the distal extremity solid for a 
variable distance; valves united along the cone bases, a slender ridge 
marking their line of junction. The shell cavity thus consisting of 2 
(lateral) halves, one of which is always occupied by a variable number 
of small very pale masses whose exact nature is unknown, but which 
seem to represent the residue of capsule formation. 
Sporoplasm.—Constantly situated in the other half.of the shell cav- 
ity, of which it occupies only a relatively very small portion; finely 
granular; no iodinophile vacuole. 
Capsules.—T wo, the largest known, filament very clearly seen, coiled; 
extrusion easily produced by potassium hydrate or ether, each capsule 
presenting as a rule a special opening placed on one side of the suture. 
Habitat.—Gall bladder (free floating in bile) of Galeus mustelus 
(=Mustelus vulgaris) smooth dogfish and of Galeorhinus galeus (= Galeus 
canis) taken at Valéry-au-Caux, by Balbiani, in August, 1891. 
1Thélohan gives the dimensions reversed (7. e,, a8 length 100, breadth 8 to 10 or 
12 ~) but this is of course a wrong orientation. Similarly with other species. 
