THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. 2OW 
Myxosporidium.—The following may refer to this stage. To me it is 
rather obscure: 
Between the tailed spores were found in great numbers protoplasmic bodies of the 
size of a blood corpuscle or smaller, which were round and contained ‘‘semen” 
(?spores). The protoplasm of these bodies wag seminal (?sporigenous). The nucleus 
was sharply defined and contained several semina (? granules). 
Spore.—Round or oval with a sharp anterior end; shell double-con- 
toured; substance homogeneous, texture reminding one of chitin, unaf- 
fected by acids and by alkaline hydrates; capsules 2, anteriorly placed; 
filaments gradually extruded under the influence of gentle heating. 
By means of staining with fuchsin or methylen blue performed after 
warming, there appeared in the spore a sharply defined “nucleus”. Tail 
single or double, consisting of a substance similar to the shell, thick at 
its origin, attenuating gradually to its free extremity; shape similar to 
that of the tail of M. psorospermicus as figured by Biitsehli.! 
 Micro-chemistry—Fuchsin and methylen blue stain the spores and 
the extruded capsular filaments, but not the shell or the tail. 
Habitat.—Cysts irregularly distributed in the interstitial connective 
tissue of the thoracic and intercostal muscles of Coregonus. Loosely 
united to the surrounding muscular tissue by spongy connective tissue 
and easily separable therefrom by its rupture. 
As to the relation of this species to the next, see next page. 
82. Myxobolus sp. incert. 
Psorosperms of muscles of Coregonus fera, Clapareéde, 1874, in Lunel’s Hist. nat. 
d. poissons du bassin du Léman, p. 113. 
Cyst.—Five in number, varying in size from that of a filbert to that 
of a small walnut. Characters constant. Contents, a milky fluid or 
(from resorption of the more liquid portions) a caseous mass. This 
fluid or semifluid mass consists of psorosperms in great number, with a 
granular protoplasm between them. 
Myxosporidium.—This granular protoplasm is without doubt the 
remains of the amceba at the expense of whose protoplasm, and within 
which, the psorosperms were formed. The protoplasm in fact contains 
“vacuoles” (pansporobhaists) which in the beginning are destitute of 
proper walls, but which form the point of departure for psorosperm 
production. The examination of one fragment of protoplasm is sufficient 
to show all transitions between the simple vacuoles (pansporoblasts) and 
the vesicles containing the 2 oval corpuscles [capsules] characteristic 
of the psorosperm, and a third corpuscle, whence will be derived the 
“blastema” (sporoplasm) which fills the posterior part of the body of the 
psorosperm. It is only a step from these vesicles to the imperfectly 
developed psorosperms disseminated through the protoplasm. These 
last already show all essential traits of the fully developed psorosperin 
' Bronn’s Thier-Reich, 1882, 1, pl. 38, fig. 16. 
F c——l7 
