240 REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 
60. Myxobolus spheralis Gurley, 1893. 
(Psorosperms of Coregonus fera, Claparéde, 1874, in Lunel’s Hist. Nat. d. poissons 
du bassin du Léman, pp. 113-14. ) 
Myzxobolus spheralis, Bull. U.S. Fish Com. for 1891, x1, p.415; Myxobolus sphe- 
ralis [error] Braun, 1894, Centralbl. f. Bakt. u. Parasitenkde, Xv, p. 87. 
Cyst.—Diameter, 0-25 to 0-33 mm. 
Myxosporidium unknown. 
Spore.—Very different from those contained in the cysts of the 
muscles of the same fish, untailed, perfectly spherical, 9 ~ in diameter, 
containing a single spherical, very strongly refringent “nucleus” and 
some small granules. Some cysts contain spores with less refringent 
nuclei and with very numerous small granules. This difference is per- 
haps only one of age. 
Habitat.—Cysts imbedded by thousands in the mucosa of the branchiz 
of Coregonus fera Jur. Their abundance gives to the branchie a gray- 
ish color apparent at the first glance. 
Rtemarks.—Claparéde remarks that it might naturally be supposed 
that a generic bond exists between the small cysts of the branchie and 
the large cysts of the muscles, but observation was unable to justify 
this hypothesis. 
61. Myxobolus sp. incert. Pl. 28, fig. 6. 
Psorosperms of Lucioperca sandra, Miiller, 1841, Miiller’s Archiv., pp. 480-6, pl. 
16, figs. 3a-l ; ib., Miiller, 1843, Rayer’s Archiv. de Méd. comp., I, pp. 222-6, 
pl. 9, fig. 3a-l; ib., Dujardin, 1845, Hist. Nat. d. Helminthes, p. 644; ib., 
Robin, 1853, Hist. Nat. d. Végét. Parasites, p. 295, pl. 15, fig. 5. 
Cysts.—Flat white vesicles or pustules, 1-09 to 2:18 mm. ($ to 1/”’) in 
diameter, usually few and discrete; contents a small quantity of gran- 
ular matter, mostly, however, consisting of the spores. 
Myxosporidium unknown. 
Spore.—Almost exactly round, untailed or very rarely (once in 200 
to 300 times) tailed, the tailed forms occurring in the same cyst and 
resembling especially M. schizurus, from which species, however, they 
differ in having the tail no longer or only a little longer than the body; 
with double-contoured border, thickness equal to one-half the breadth; 
ridge present; capsules 2, of equal size, converging and appearing as 
though united by a knot at their anterior extremities (fig. 6a). Among 
multitudes of typical specimens, Miiller says an occasional one is seen 
containing 3 bodies, the third being placed behind and between the 
other two. Spore frequently showing a dark punctule just behind the 
posterior end of each capsule which sometimes simulates an oblique 
line extending from the border to the capsules; at others, a slight 
projection of the shell. . 
Development.—Traced (naturally enough, but erroneously ') by Miiller, 
as follows: (1) Spores occurin which the capsules are no longer at the 
‘It must be remembered that Miiller was not aware of the existence of the myxo- 
sporidium. Recently Mingazzini has attempted to revive this view of the office of 
the capsules (see p. 87). 
