THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. 181 
The presence of a contractile vacuole in the adult, the peculiarities 
in the process of spore formation, the falling to pieces of the nucleus, 
the apparent absence of pansporoblasts, the occurrence of reproduction 
only at and as the end of the life cycle, and the further multiplication 
by the division of fully formed spores, all absolutely contraindicate any 
myxosporidian affinities. Further, the constant presence of pigment! 
corroborates this conclusion, which is still further enforced by negative 
evidence from the structure of the spore, the most prominent feature ot 
which is, of course, the absence of the capsule. Indeed it seems safe to 
go further and say that no organism with a contractile vacuole can, in 
the present state of our knowledge, be regarded as sporozoan (ef. Lan- 
kester, Encycl. Britan., 1885, 9 ed., x1x, p. 854). 
PROBABLY MYXOSPORIDIA. (Imperfectly described.) 
7. Genus et sp. incert. 
Amecebiform corpuscles of gills of Cyprinus brama, Lieberkiihn, 1854, Miiller’s 
Archiv., pp.6, 7; ? ib. of heart-blood of same fish,? p. 14; ef. also Miiller, 
Miiller’s Archiv., 1841, pp. 491-2. 
Cyst.—Membrane so transparent that all details could beas well seen 
before as after expression of its contents. Contents ‘“psorosperms” 
and amcebiform corpuscles, or amoebiform corpuscles only. 
Myxosporidium.—Numerous, partly granular, partly granule-free, 
the latter usually smaller than the former, alterations of appearance 
very manifold, processes rather sharp than blunt, size not equal to that 
of a blood corpuscle of the fish; granules extremely small, held together 
by a mucoid substance. 
Spore.—Unknown. 
Habitat.—Eneysted in the gills of Abramis brama lL. (bream) in 
November. 
Remarks.—Its habitat suggests that this species is probably a Myxo- 
bolus. 
8. Genus et sp. incert. 
Sarcode masses of Perca fluviatilis, Lieberkiihn, 1854, Miiller’s Archiv., p. 353. 
Cyst.—Apparently no true cyst (see mention below of membrane). 
Myxosporidium.—Consisting of granular protoplasm presenting a 
great similarity to that of Chloromyxum mucronatum, very variable in 
appearance, oval, lenticular or dendroidly branched. Size 27 to 440 wu 
(xo to $/"); some specimens surrounded by a structureless membrane, 
others not; sometimes the whole substance is seen to have fallen apart 
1 While it is, of course, not contended that this alone would suffice to prove a species 
nonmyxosporidian, pigmentation, such as exists in the Cyclops cyst, would raise a 
strong presumption against its myxosporidian nature. 
?Those [amcebiform corpuscles] of the heart blood of Cyprinus brama completely 
parallel in their form the above-described amcebiform masses found on the gills of 
the fish, and are differentiated among themselves in the same way as the gill forms 
[i.e., they are either granular or granule-free], Their movements are, on account 
of their small size, difficult to observe. 
