194 REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 



back. Tlie forms habitant on these 2 tisbos are identical, (lifferin<^ only 

 a little in tlie size of the cysts (jill./i(/e Thelohan). Snbcutaneous cysts 

 of Aphya alba { = Qohius minutus and G. albus). In the last the deform- 

 ity is even greater than in 0. aculeatus. 



Xature. — For Gbige's opinion, see p. 93. 



Effects. — Even where the tumors occupy the internal surface of the 

 opercle the fish did not appear to be hampered in its functions. Tliose 

 which carry the tumors on the fins, nevertheless move the latter as 

 freely and actively and execute all movements with the same facility as 

 the sticklebacks not so affected. The tumors nmy be carefully removed 

 without injuring the lish, which appears as well as ever after the oi)era- 

 tion. Upon careful dissection, Gluge was unable to find any change in 

 the intestine or in the blood. Thdlohan (1890, p. 203) states that in 

 certain cases the muscles are comjiressed and atroi>hied by pressure of 

 the tumors, and the viscera are also compressed and no longer present 

 their normal iiosition or relations. 



II. PLEISTOPHORA Gurley, 1893. 



Etj'mology: Tr/leiorof, very niiiny; (peptir, to cari'y. 



Bull. U.S. Fish. Com. for 1891, xi, pp. 409, 410; ib., Brann, 1894, Centralbl. f. 

 Bakt. u. Parasitcukde, XV, p. 86. 



Definition (provisional as regards negative characters). — Gluffeidw 

 destitute of a myxosporidium and in which the pansporoblast produces 

 an inconstant but large number (always more than 8) of spores ; panspo- 

 roblast membrane subpersistent as a polysporophorous vesicle j type, 

 P. tijpicalis. 



29. PIei3tophora typicalis Gurley, 1893. 



(Corpuscles of Cottus scorjpio Tli<51nlian, 1890, Anual. do Microgr., ii, pp. 203, 212; 

 ib. Tht^lohan, 1891, .Journ.de. Microgr., xv, pp. 145,146; ib. Tliololian, 1891, 

 Compt. Reud.bebdom. Soc. Biol. Paris, iii, pp. 27,28; ib. of CoUus (error) 

 Th61ohan, 1891, Compt. Reud. Acad. Sci. Paris, cxii, p. 170; ib. Pfoiffer, Die 

 Protozoen als Krankbeitserreger, 2 ed., pp. 113-115 ; ib. Thdloban, 1892, 

 Compt. Reud. liobdom .Soc. Biol. Paris, iv, pp. 82, 83 ; ib. Thfrlohan & Henne- 

 guy, 1892, ibid., p. 586; ib. Tli61ohau, 1892, Bull. Soc. philomat. Paris, iv, 

 pp. 165, 174; ib. Henneguy & Tb61ohan, 1892, Anual. de Microgr., IV, pp. 

 618,619,622,631,636.) 



ricistophora tiipicaJis, Bull. U. S. Fish Com. for 1891, xi, p. 410; ib. Braun, 1894, 

 Centralbl. f. Bakt. u. Parasitenkde, xv, p. 86. 



Cyst. — None. 



S^yore formation. — Thelohan observed between tlie fibrillre small sepa- 

 rate masses of protoplasm, each with a distinct membrane and nuclei. 

 These masses woic 4/1^ long by 2-5 to 3/^ broad. Thelohan believed them 

 to represent the first stages of development, but emitted this opinion 

 with reserve, not having seen a sufficient series of stages. Some pro- 

 toplasmic masses inclosing several nuclei exhibit, however, intermediate 

 stages between the masses already described and the pansporoblasts. 



* "4 Cent." in Joam. de Microgr., xv, p. 146. 



