~~ 
THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. “1 
GENERAL DESCRIPTION OF THE SUBCLASS MYXOSPORIDIA. 
I—NOMENCLATURE AND DEFINITION. 
SUBKINGDOM PROTOZOA, 
Class Sporozoa Leuckart, 1879 (emendated), 
The following is Leuckart’s definition! verbatim, with the exception 
of the proposition of the Gregarinida as the type order, a proposition 
that is implied by Leuckart’s language. The words inclosed in brackets 
should, as shown by subsequent observations, be omitted from the 
class definition. 
Unicellular parasites [of stable body-form], destitute [of pseudopodia and] of 
ciliz. covered with a smooth, more or less solid cuticle. At the anterior end not 
seldom a proboscidiform attachment-apparatus. Movements on the whole little 
striking, worm-like or feebly ameboid. Mode of life always parasitic; nutrition 
by endosmosis. Reproduction by more or less hard-shelled spores (pseudonavicelle ; 
psorosperms) formed in the interior of the protoplasm in variable but very consid- 
erable numbers,” either progressively or simultaneously (in the latter case at the 
termination of growth and after encystment). Germinal portion of spore consisting 
of falciform protoplasmic rods (Gregarinida; Coccidia) or a single protoplasmic mass 
(Myxosporidia); type order Gregarinida. 
Subclass Myxosporipia Biitschli, 1881. 
Zoolog. Jahres-Ber. f. d. J. 1880, 1, p. 162; ib., Biitschli, 1881, Ztschr. f. wiss. Zool., 
XXXV, pp. 6380, 650; ib., Biitschli, 1882, Bronn’s Thier-Reich, 1, p. 590; ib. of all 
subsequent authors; Myxosporide (Psorospermide J. Miiller)® Ziirn, 1882, 
Die thierischen Parasiten, Weimar, p. 816; Myxospora‘ (error) Mégnin, 1885, 
Compt. Rend. hebdom. Soc. Biol. Paris, u, p. 447; subclass Myxosporidia, Lan- 
kester, 1885, Encycl. Britan., 9 ed., x1x, p. 855; ‘‘Psorospermide J. Miiller,’””3 
Koch, 1887, Encyklop. d. gesammt,. Thierheilkde u. Thierzucht, 1v, p. 94. 
THE SUBCLASSIC DESIGNATION. 
Miiller, in 1841, denominated the forms observed by him merely as 
“Psorospermien.” Everything points to the conclusion that this name 
was used merely indefinitely as a group designation. He neither 
proposed. it as a generic name nor did he anywhere latinize it. He 
1 Die Parasiten des Menschen, 1879, 2 ed., p. 241. 
2Compare Bisporogenesis in index. 
3 An error; Miiller did not propose any such family. Ziirn’s definition is quoted 
to show the errors (italics) : 
“Order 4. Myxosporide (Psorospermide, J. Miiller). Frequent in and on fishes 
and Amphibia. The nucleus-less, often granulated protoplasm, is surrounded tube- 
like by a cuticle. From the young protoplasm of these tubes, single or double con- 
toured, fusiform, oval, or round spores originate without previous encystment. In the 
spore originate one or several germs, mostly resembling a nucleus-less, but somewhat 
granulated plasma-globule, or representing a needle-shaped (stabf drmige) body. The 
spore membrane often provided with 1 or 2 filaments) bursts in order to free the only 
very rarely motile germs.” 
4 Psorospermies des poissons ou Myxospora de Biitschli.” 
