THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. 249 



Cyst not deseribetl ; inyxosporidiiiin unknown. 



Spore. — Perfectly transparent, colorless, much larger than any of 

 Miiller's species, body elon<>ate, strongly ventricose-elliptic, 17-3// long 

 by 5'Si.i broad; shell bivalve, of firm texture, enabling the spore to 

 retain its shape on drying, splitting open after several days' immersion 

 in water, the resulting median fissure extending nearly to the root of 

 the tail; tail present, simple, diminishing in thickness from origin to 

 its fine iiointed extremity, about as long as or a little longer than the 

 body (in 1 si)ecimen 2J times that length), often more or less deflected 

 from the line of the antero posterior axis of the body; contents of body 

 cavity perfectly clear, granule-free, showing no trace of structure other 

 than the caj^sules; capsules 2 (on transverse view only 1) of equal 

 size, pale yellow, subcylindrical, situated at the anterior pole, diverg- 

 ing posteriorly or adnate to each other along their inner borders; in a 

 single specimen begimung as a single cylindrical tube (i the length 

 of the capsules), which divided j)osteriorly into the 2 capsules; the 

 latter diverging from their origin to their blind posterior extremities 

 (fig. d). Capsules become strongly wrinkled on drying. 



Ilahitaf. — On Acerina cernua L. ; collected March 14, 1837. 



73. Myxobolus strongylurus Gurley, 1893. PI. 31, fig. 5. 



(Psorosperms of Sijnodonfifi schal, Miiller, 1841, Miiller's Arcliiv., pp. 480-1, pi. 16, 



fig. 2; !&., Miiller, 1813, Riiyer's Arcbiv. tie Med. Comp., i, pp. 222, 227, pi. 9, 



fig. 2; ih., Robiu, 1853, Hist. Nat. de Veget. Parasites, p. 295, pi. 14, fig. 4.) 



Myxobolus strongylurus, Bull. U. S. Fish Com. for 1891, xi, p. 417; Myxobolus 



strongylura [error], ttraun, 1891, Centralbl. Bakt. u. Parasiteukde, xv, p.87. 



Cijut.—Over 2-18 mm. (1'") in length. 



Myxosporidium unknown. 



Spore. — Body blunter anteriorlj^ than in ilJf. scJiizxrus; length without 

 tail 9;< (0-0040'") ; breadth, 5-4/./; tail always undivided, very peculiar 

 in being constantly oblique in the longitudinal i)lane, appearing straight 

 when seen in transverse view; capsules, 2, of equal size. Spore some- 

 times showing at posterior end of capsule a dark punctule which occa^ 

 sionally causes a slight projection of the shell at this part. 



Habitat. — Encysted in skin of cephalic region of SynodoHtin schal 

 from the Nile. 



74, Myxobolus monurus Gurley, 1893. PI. 32, figs, 3, 4. 



(FsoTosiwrms o{ A2)hre(loclerus sayanus Ryder, 1880, Anier. Nat., xiv, i)p. 211-2, 

 figs. 1, 2; parasite of Aphredoderus savanus^ [error] Tli(^loban, 1892, Bull. 

 See. pbilomat. Paris, iv, p. 177.) 



Myxobolus monurus, Bull. U. S. Fish Com. for 1891, xi, p, 416; ib. of Aphrodode- 

 rus [error] sayanus Braun, 1894, Ceutralbl. Bakt. u, Parasiteukde, xv, p.87. 



C}/st. — Lenticular, large, bulging, white, opa(iue, numerous (about 20 

 in the only fish seen), imbedded in the subcutaneous muscles, arranged 

 as a rule in pairs on the opposite side of the body of the fish; mem- 

 brane very thin; contents, a thick, white, creamy mass, (M)ntaining 

 multitudes of spores and of excessively minute round granules. 



'" The parasite described by .T. Ryder in Aphrcdodcrus savanna constitutes prob- 

 ably a fourth species" [of Th<)l()liaii's genus Hiuunjuya]. 



