256 REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 
80. Myxobolus pscrospermicus Thélohan, 1892. PI. 34. 
(Psorosperms of Perca fluviatilis, Biitschli, 1882, Bronn’s Thier-Reich, 1, pl. 38, 
fig. 16; ib., Balbiani, 1883, Journ. de Microgr., VII, pp. 201, 203, fig. 42; 
psorosperms of Hsox lucius, ibid., pp. 201-2, fig. 41; ib., Balbiani, 1884, Légons 
sur les Sporozoaires, p. 132, fig. 37; psorosperms of Perca fluviatilis, ibid., 
p. 133, fig. 38; ib., Lankester,1885, Ency. Britan.,9 ed., XIx, p. 855, fig. Xv, 
43, 44; ib., Thélohan, 1889, Compt. Rend. Acad. Sci. Paris, crx, p. 604; ib., 
Thélohan, 1890, Annal. de Microgr., 11, pp. 202, 207, 211, figs. 5-7; ib., 'Thé- 
lohan, 1890, Compt. Rend. hebdom. Soc. Biol. Paris, 1, p. 604; tailed pso- 
rosperms of pike, ibid.; psorosperms of Perca fluviatilis, Pfeiffer, 1890, Die 
Protozoen als Krankheitserreger, 1 ed., p. 43; ib., Pfeiffer, 1891, ibid., 2 ed., 
p. 130.) 
Henneguya psorospermica, ! Bull. Soc. philomat. Paris, Iv, pp. 167, 176. 
Myzxobolus psorospermica Gurley, 1893, Bull. U. 8. Fish Com. for 1891, x1, p. 418. 
Henneguya psorospermica Braun, 1893, Centralbl. Bakt. u. Parasitenkde, xIv, 
p. 739. 
Myzxobolus psorospermica, Braun, 1894, Centralbl. Bakt. u. Parasitenkde,xv, 
p. 87. 
Cyst and myxosporidium not described. 
Spore.—Anterior extremity obtuse; length, 35 to 40 yu (Thélohan, 
1892; 36 », Balbiani for spore of Lucius; 30 4, Thélohan, 1890, for spore 
of Perca); breadth, 4 y (Thélohan, 1890). Tail curved close against the 
body during development, becoming straight only after the rupture of 
the pansporoblast membrane; caudal inféex, 1. Capsules, 6 to 8 win 
length. Maximum number of nuclei, 3; vacuole present (Thélohan, 
1890). 
Habitat.—Branchie of Lucius lucius L. (pike) and of Perca fluviatilis 
(yellow perch). 
Remarks.—In view of Thélohan’s positive statement as to the identity 
of the forms habitant on the branchie of LZ. lucius and P. fluviatilis, I 
believe we are justified in referring all the forms figured to one species, 
although fig. 34 (pl. 4) differs somewhat from the rest. 
81. Myxobolus kolesnikovi Gurley, 1893. PI. 35. 
(Psorosperms of Coregonus, Kolesnikoff, 1886, Vet. Vestnik Kharkoff, vy, pp. 
242-248, plate, figs. 1-3.) 
Myzxobolus kolesnikovi of Coregonus fera [error],? Bull. U. 8. Fish Com. for 1891, 
XI, p. 417. 
Cyst.—Numerous, sometimes as many as 80, length 10 to 30 mm., 
breadth 7 to 20 mm., spherical or oval, bean-shaped, yellowish-white, 
surface of cyst-wall smooth and shining, membrane of the thickness of 
a cigarette paper, rupturing by the slightest pressure of the forceps. 
Contents thick, yellowish-white, creamy, consisting of spores and an 
oily substance. 
1 “One finds on the branchia of the pike and of the perch a myxosporidian abso- 
Jutely identical in the two cases and which it is certainly necessary to consider as 
constituting but a single species” (Thélohan.) 
The words ‘‘ Psorospermies de J. Miiller” were evidently attached to this species 
inadvertently. Miiller knew no species on the branchiw of Z. lucius. In this fish 
he observed them only in the orbit. 
2 Kolesnikoff does not mention any species. 
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