THE MYXOSPORIDIA, OR PSOROSPERMS OF FISIIES. 239 
56. Myxobolus sp. incert. Pl. 28, fig. 4. 
Cyst and myxosporidium unknown. 
Spore.—Broadly elliptic; length, 14 4; breadth, 10 ~; thickness, 5 7; 
Shell bivalve; valves equally convex; ridge index about 0:25, Cap- 
sules 2, equal; capsular index not quite 0°50. Sporoplasm showing a 
clear, round space, without doubt the vacuole. 
Habitat.—Body cavity of Carassius carassius L. (goldfish), from Ger- 
many. 
Remarks.—For this species I am indebted to Dr. C. W. Stiles, who 
mounted the spores in Leipsic. The exact locality whence the host 
came is unknown. The specimen was mounted unstained in Farrant’s 
solution. For this reason the vacuole could not be stained or the 
nuclei be determined. 
57. Myxobolus ? obesus Gurley, 1893. Pl. 28, fig. 7. 
(Psorosperm of the “Ablette,” Balbiani, 1883, Journ. de Microgr., vir, p. 203, 
fig. 43; ib. Balbiani, 1884, Légons sur les Sporozoaires, p. 133, fig. 39.) 
Myxobolus obesus, Bull. U. 8S. Fish Com. for 1891, x1, p. 415; ib. of Aldurnus 
lucidus! Braun, 1894, Centralbl. f. Bakt. u. Parasitenkde, xv, p. 87. 
No description. 
Habitat.—On Alburnus alburnus Ih. 
58. Myxobolus cycloides Gurley, 1893. Pl. 28, fig. 5. 
(Psorosperms of Cyprinus rutilus, Miiller, 1841, Miiller’s Archiv., pp. 481, 
486, pl. 16, fig. 4d-g; ib.,2 Creplin, 1842, Wiegmann’s Archiv. f. Natur- 
gesch., I, p. 63 (footnote); ib., Miiller, 1843, Rayer’s Archiv. de. Méd 
comp., I, p. 226, pl. 9, tig. 4d-g; ib., Rayer, 1843, ibid., p. 269; ib., (pars) 
Robin, 1853, Hist. Nat. Végét. Parasites, p. 299, pl. 14, fig. 6.) 
Myxobolus cycloides, Bull. U.S. Fish Com. for 1891, x1, p.415; ib., Braun, Cen- 
tralbl. f. Bakt. u. Parasitenkde, xv, p. 87. ; 
Cyst.—Not described. Creplin states that the membrane is very 
delicate and that it is “dissolved” by water. 
MyxosporWium unknown. 
Spore.—Subeircular-ovate or broadly rounded-elliptic, resembling M. 
circularis; length, 12 yu (0°0054/"’), 
Habitat.—Encysted, most frequently on inner surface of opercle and 
particularly on the pseudobranchie (Nebenkiemen) of Leuciscus rutilus 
from German rivers. Disease of very frequent occurrence, principally 
in May and June. Creplin’s specimens were taken May 8, 1835, and 
January 31, 1839. 
59. Myxobolus sp. incert. 
Myxosporidian spore of Gardon, Thélohan, 1889, Compt. Rend. Acad. Sci. Paris, 
CIXx, p. 921. 
Spore.—Vacuole present; maximum number of nuclei, 3. 
Habitat.—On the “ Gardon.” At present this form is entirely indeter- 
minate, as M. Thélohan informs me (letter, 1893) that Gardon is applied 
indiscriminately to both Leuciscus rutilus and L. erythrophthalmus. 
1The question between the two specific names is merely that of the advisability 
of the use of a specific name identical with the generic, 
?Creplin compares his form to Miiller’s, fig. 4d. 
