7. 
THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. 195 
Pansporoblast spherical, average diameter 15 to 18 4; membrane 
thin, transparent, containing, besides fully developed spores, sporo- 
blasts in different stages of development, some of them measuring 2°5 
to 3 4, and containing one or several colored granules representing 
nuelei. 
Spore.—Ovoid, resembling that of Glugea anomala; length, 3 y; 
breadth, 1:5 to 2; a single capsule with a filament is present; large 
extremity showing a mass refractory to staining fluids, the remainder 
of the spore cavity containing sporoplasm, and a body apparently repre- 
senting the nuclear element of the spore, staining strongly with reagents, 
and in certain cases decomposable into separate granules whose num- 
ber never exceeds 4. 
Habitat.—Muscles of Cottus scorpio (sculpin); position interfibrillar. 
Effects —Diseased mass forming small white streaks of an averaye 
size of 5 to6 mm. by 3 mm., consisting of spores. The fibers affected 
increase in bulk; they are filled with the pansporoblasts disposed 
without regular order between the fibrille, which latter become sepa- 
rated and distorted, without, however, presenting any alteration of 
structure or diminution in the clearness of their tranverse striation. 
Ill, THELOHANIA Henneguy, 1892. 
Etymology: Thélohan. 
In Thélohan, Bull. Soc. philomat. Paris, 1v, p. 174, footnote; ib. Henneguy, in 
Henneguy and Thélohan, Annal. de Microgr., Paris, 1892, tv, p. 639; ib. 
Gurley, 1893, Bull. U. 8. Fish Com. for 1891, x1, pp. 409-410; ib. Braun, 
1893, Centralbl. f. Bakt. u. Parasitenkde, xiv, pp. 739-740; ib. Braun, 1894, 
Centralbl. f. Bakt. u. Parasitenkde, xv, p. 86. 
Dejinition' (provisional as regards negative characters).—Gilugeide 
destitute of a myxosporidium and in which the pansporoblast pro- 
duces constantly 8 spores; pansporoblast membrane subpersistent as 
an octosporophorous vesicle; type 7. giardi.’ 
Henneguy and Thélohan remark that in this genus the spores unques- 
tionably approximate those of Glugea anomala and those of Pleistophora. 
The number of spores formed in the pansporoblast and the absence of 
a myxosporidium differentiate Thelohania from Glugea. On the con- 
trary, the last character and the subpersistence of the pansporoblast 
membrane as a sporophorous vesicle, approximate it to Pleistophora. 
1 Henneguy’s definition is: 
‘Spores pyriform, with one polar capsule at the small extremity and, at the opposite 
extremity, a clear vacuole with contents not colorable by iodine. Sporoblasty pro- 
ducing only 8 spores surrounded by an envelope persisting after theformation of 
these last; no plasmic mass, properly speaking.” 
As constituted by Henneguy the genus included only 3 species, T. octospora, T. giardi 
and T. contejeani. 
Type proposed by the author in Bull. U.S. Fish Com. for 1891 (1893), x1, p. 410. 
