256 EEPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 



80. Myxobolus psorospermicus Thelolian, 1892. PI. 34. 



(Psorospcrms of Pcrca finviatilis, Biitschli, 1882, Bronn's Thier-Reich, I, pi. 38, 

 tig. 16; ih., Balbiani, 1883, Journ. do Microgr., vii, pp. 201, 203, fig. 42; 

 psorospermsof jKsoj; luciiis, iZxVZ., pp. 201-2, fig. 41 ; ib., Balbiani, 1884, L^^ons 

 sur les Sporozoaires, p. 132, fig. 37; psorosperms of Perca fluviatllis, ibid., 

 p. 133, fig. 38; ib., Lankester,1885, Ency. Britau., 9 ed., xix, p. 855, fig. xvii, 

 43, 44; ib., Tli^loban, 1889, Compt. Reud. Acad. Sci. Paris, cix, p. 604; ib., 

 Th^lobaii, 1890, Aiinal. de Microgr., ii, pp. 202, 207, 211, figs. 5-7; ib., Th6- 

 lohan, 1890, Compt. Rend, hcbdom. Soc. Biol. Paris, ii, p. 604; tailed pso- 

 rosperms of pike, ibid.; ])SOTOSi)evms of Perca flu mat ilis, Pfeiii'er, 1890, Die 

 Protozoen ale Krankheitserreger, 1 ed., p. 43; ib., Pfeiffer, 1891, ibid., 2 ed., 

 p. 130.) 



Heiniegxyapsorospermica, ^ Bull. Soc. philomat. Paris, iv, pp. 167, 176. 



Myxobolus psorospermica Gurley, 1893, Bull. U. S. Fish Com. for 1891, xi, p. 418. 



Henncijnya psorospermica Braun, 1893, Ceutralbl. Bakt. u. Parasiteukde, xiv, 

 p. 739. 



Myxobolus psorospermica, Braun, 1894, Ceutralbl. Bakt. u. Parasitenkde^xv, 

 p. 87. 



Cyst and inyxosporidium not described. 



Spore. — Anterior extremity obtuse; length, 35 to 40 /u (Tb61ohan, 

 1892; 36 //, Balbiani -for spore of Lucius; 30 //, Thelolian, 1890, for spore 

 of Perca) ; breadth, 4 ja (Th<51ohan, 1890). Tail cnrved close against the 

 body during development, becoming straight only after the rupture of 

 the pansporoblast membrane; caudal index, 1. Capsules, 6 to 8 /.i in 

 length. Maximum number of nuclei, 3; vacuole present (Thelohau, 

 1890). 



Hahitat. — Branchiae of Lucius lueius L. (pike) and of Perca Jluviatilis 

 (yellow jjerch). 



Remarlis. — In view of Thelohan's positive statement as to the identity 

 of the forms habitant on the branchi;ie of L. lueius and P. fluviatilis, I 

 believe we are justified in referring all the forms fignred to one si)ecies, 

 although fig. 34 (jd. 4) differs somewhat from the rest. 



81. Myxobolus kolesnikovi Gurl«y, 1893. PI. 35. 



(Psorosperms of Corer/onus, Kolesnikoft", 1886, Vet. Vestnik Kharkofi', v, pp. 



242-248, plate, figs. 1-3.) 

 Myxobolus kolesnikovi of Coreyonusfera [error],- Bull. U. S. 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, beau-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. 



' "One finds on the branchise of the pike and of the perch a niyxosporidian abso- 

 lutely identical in the two cases and which it is certainly necessary to consider as 

 constituting but a single species" (Th^lohan.) 



The words " Psorospcrmies de .J. Miiller" were evidently attached to this species 

 inadvertently. Miiller knew no species on the brancliiae of L. lueius. lu this fish 

 he observed them only in the orbit. 



2 Kolesnikoft^' does uot mention any species. 



