244 REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 
(yellow perch) in German rivers and in the Irtisch (Miiller). Scales 
(Lieberkiihn; Bessels). Disease not common. 
Remarks.—Bessels’s form seems probably referable here, as he speaks 
of having observed the longitudinal splitting into 2 symmetrical halves 
of an ellipsoid form. 
67. Myxobolus sp. incert. Pl. 29, fig. 8. 
Psorosperms of Leuciscus rutilus, v. d. Borne, 1886, Handb. d. Fischzucht u. 
Fischerei, p. 211, fig. 215. 
No description. 
Habitat.—On Leuciscus rutilus L. 
68. Myxobolus ?? zschokkei Gurley, 1893. PI. 31, fig. 1. 
(Psorosperms of Coregonus fera, Zschokke, 1884, Archiv. de Biol., v, pp. 234-5, 
pl. 10, fig. 16; ib., Linton, 1891, Bull. U. S. Fish Com. for 1889, 1x, p. 101.) 
Myzxobolus ?? zschokkei, Bull. U. S. Fish Com. for 1891, x1, p. 416. - 
Cyst.—Oval, white, size varying from that of a small pea to that of 
a large nut; multiple, sometimes as many as 30 on one fish, the largest 
usually situated in dorsal muscles; cyst membrane thick, very resist- 
ant, without apparent structure; contents a milky fluid, occasionally a 
caseous mass, coagulable by alcohol. 
Myxosporidium unknown. 
Spore.—I quote in substance Zschokke’s description: 
Body lenticular or oval, a little wider in front than behind; often bearing in front 
a blunt prolongation; posteriorly one distinguishes 2 ‘ tails” (queues), 6 to 8 times 
longer than the body, attenuating posteriorly, curved and undulating ; the number 
of 2 “tails” is constant; at the pole opposite to the ‘‘tails” are 2 oval, trans- 
parent anteriorly-converging vesicles; one sometimes sees, however, an extremely 
fine canal extending from the posterior end of each vesicle to the base of the corre- 
sponding ‘‘ tail”; the vesicles then probably play here also the role of receptacles for 
the ‘‘ tails.” Round refractile globules are also seen at the bases of the vesicles; the 
remainder of the body is filled by a homogeneous plasmic mass, which frequently 
contracts to the center of the body cavity, forming a clearly distinct round or oval 
mass. 
Habitat.——Encysted in the subeutaneous and superficial intermuscular 
tissue of Coregonus fera. Observed during April and May. Disease 
stated by fishermen to be of very frequent occurrence. 
Effects.—The skin is irregularly swollen and the scales fall easily. 
As to myxosporidiosis of Coregonus, see also p. 233. 
This form is a very puzzling one. As appears from the above 
description and from the figure (pl. 31, fig. 1), the 2 structures, called 
by Zschokke “tails” (queues), are seen at one end, and at the opposite 
end are 2 structures (the “ vesicles” of the above description) approxim- 
ating to the position of and presenting somewhat the appearance usual 
to the capsules, and Zschokke considers them to be the capsules. 
They converge, as do the capsules of most species, toward the end of 
the spore, at or near which they are situated, and they diverge in the 
opposite direction. From these facts one would be inclined to pro- 
nounce this end (viz, the one at which these “ vesicles ” are placed and 
toward which they converge) the anterior, and the opposite one (the 
