THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. 249 
Cyst not described; myxosporidium unknown. 
Spore.—Perfectly transparent, colorless, much larger than any of 
Miiller’s species, body elongate, strongly ventricose-elliptic, 17-34 long 
by 5:8 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 pointed extremity, about as long as or a little longer than the 
body (in 1 specimen 24 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 capsules; 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 beginning as a Single cylindrical tube (4 the length 
of the capsules), which divided posteriorly into the 2 capsules; the 
latter diverging from their origin to their blind posterior extremities 
(fig. d). Capsules become strongly wrinkled on drying. 
Habitat.—On Acerina cernua L.; collected March 14, 1837. 
73. Myxobolus strongylurus Gurley, 1893. Pl. 31, fig. 5. 
(Psorosperms of Synodontis schal, Miiller, 1841, Miiller’s Archiv., pp. 480-1, pl. 16, 
fig. 2; ib., Miiller, 1843, Rayer’s Archiv. de Méd. Comp., 1, pp. 222, 227, pl.9, 
fig. 2; ib., Robin, 1853, Hist. Nat. de Végét. Parasites, p. 295, pl. 14, fig. 4.) 
Myxobolus strongylurus, Bull. U. S. Fish Com. for 1891, x1, p. 417; Myzxobolus 
strongylura [error], Braun, 1894, Centralbl. Bakt. u. Parasitenkde, xv, p. 87. 
Cyst.—Over 2°18 mm. (1/”’) in length. 
Myxosporidium unknown. 
Spore.—Body blunter anteriorly than in M. schizurus; length without 
tail 9u (0-0040/’); breadth, 5-4; tail always undivided, very peculiar 
in being constantly oblique in the longitudinal plane, 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.—Eneysted in skin of cephalic region of Synodontis schal 
from the Nile. 
74. Myxobolus monurus Gurley, 1893. PI. 32, figs. 3, 4. 
(Psorosperms of Aphredoderus sayanus Ryder, 1880, Amer. Nat., xIv, pp. 211-2, 
figs. 1, 2; parasite of Aphredoderus savanus' [error] Thélohan, 1892, Bull. 
Soc. philomat. Paris, Iv, p. 177.) 
Myzxobolus monurus, Bull. U. S. Fish Com. for 1891, x1, p. 416; ib. of Aphrodode- 
rus [error] sayanus Braun, 1894, Centralbl. Bakt. u. Parasitenkde, xv, p. 87. 
Cyst.—Lenticular, large, bulging, white, opaque, numerous (about 20 
in the only fish seen), imbedded in the subcutaneous muscles, arranged 
as arulein pairs on the opposite side of the body of the fish; mem- 
brane very thin; contents, a thick, white, creamy mass, containing 
multitudes of spores and of excessively minute round granules. 
1“ The parasite described by J. Ryder in Aphredoderus savanus constitutes prob- 
ably a fourth species” [of Thélohan’s genus Henneguya]. 
