194 REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 
back. The forms habitant on these 2 fishes are identical, differing only 
a little in the size of the eysts (all fide Thélohan). Subcutaneous cysts 
of Aphya alba (= Gobius minutus and G. albus). In the last the deform- 
ity is even greater than in G. aculeatus. 
Nature.—Yor Gluge’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. Those 
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 may be carefully removed 
without injuring the fish, which appears as well as ever after the opera- 
tion. Upon careful dissection, Gluge was unable to find any change in 
the intestine or in the blood. Thélohan (1890, p. 203) states that in 
certain cases the muscles are compressed and atrophied by pressure of 
the tumors, and the viscera are also compressed and no longer present 
their normal position or relations. 
II. PLEISTOPHORA Gurley, 1893. 
Etymology: wAevoroc, very many; gepev, to Carry. 
Bull. U.S. Fish. Com. for 1891, x1, pp. 409, 410; 7b., Braun, 1894, Centralbl. f. 
Bakt. u. Parasitenkde, xv, p. 86. 
Definition (provisional as regards negative characters).—Glugeide 
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; type, 
P. typicalis. 
29. Pleistophora typicalis Gurley, 1893. 
(Corpuscles of Cottus scorpio Thélohan, 1890, Annal. de Microgr., 11, pp. 203, 212; 
ib. Thélohan, 1891, Journ. de Microgr., Xv, pp. 145, 146; ib. Thélohan, 1891, 
Compt. Rend. hebdom. Soe. Biol. Paris, 111, pp. 27,28; ib. of Collus (error) 
Thélohan, 1891, Compt. Rend. Acad. Sci. Paris, cxul, p.170; ib. Pfeiffer, Die 
Protozoen als Krankheitserreger, 2 ed., pp. 113-115; ib. Thélohan, 1892, 
Compt. Rend. hebdom.Soc. Biol. Paris, lv, pp. 82, 83; ib. Thélohan & Henne- 
guy, 1892, ibid., p. 586; ib. Thélohan, 1892, Bull. Soc. philomat. Paris, rv, 
pp. 165,174; ib. Henneguy & Thélohan, 1892, Annal. de Microgr,, Iv, pp. 
618, 619, 622, 631, 636.) 
Pleisiophora typicalis, Bull. U.S. Fish Com. for 1891, x1, p. 410; 1b. Braun, 1894, 
Centralbl. f. Bakt. u. Parasitenkde, xv, p. 86. 
Cyst.—None. 
Spore formation.—Thélohan observed between the fibrillz small sepa- 
rate masses of protoplasm, each with a distinct membrane and nuclei. 
These masses were 4,11 long by 2°5 to 3u broad. Thélohan 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. 
14 Cent.” in Journ. de Microgr., xv, p. 146, 
