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 

 inyxosporidian 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, tlie 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 (cf. Lan- 

 kester, Encycl. Britan., 1885, 9 ed., xix, p. 854). 



PROBABLY MYXOSPORIDIA. (Imperfectly described.) 



7. Genus et sp. incert. 



AmccLiform corpuscles of gills of Cyjirinu/t hrama, Lieberkiihn, 1854, Miiller's 

 Archiv., pp.0, 7; ? ib. of heart-blood of same lish,* p. 14; cf. also Miiller, 

 Miiller's Archiv., 1841, pp. 491-2. 



Cyst. — Membrane so transparent that all details could be as well seen 

 before as after expression of its contents. Contents "psorosperms" 

 and amoebiform 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 sliarp than blunt, size not equal to that 

 of a blood corpuscle of the fish; granules extremely 8nial], held together 

 by a mucoid substance. 



Spore. — Unknown. 



Habitat. — Encysted in the gills of Ahramin hrama L, (bream) in 

 November. 



Eemarks. — Its habitat suggests that this species is probably a Myxo- 

 holus. 



8. Genus et sp. incert. 



Sarcode masses of Perca Jluviaiilis, Lieberkiihn, 1854, Miiller's Archiv., p. 353. 



Cy.'<t. — Apparently no true cyst (see mention below of membrane). 



Myxosporidium. — Consisting of granular "protoplasm presenting a 

 great similarity to that of Chloromyxum viucronatum, very variable in 

 appearance, oval, lenticular or deiulroidly branched. Size 27 to 440 jj 

 (sV to ^'"); some specimens surrounded by a structureless membrane, 

 others not; sometimes the whole substance is seen to have fallen apart 



• While it is, of course, not contended that this alone would suffice to prove a species 

 nonmyxosporidian, pigmentation, such as exi.sts in the Cijdops cyst, would raise a 

 strong presumption against its myx(is])oridian nature. 



2 Those [amuibiform corpuscles] of the heart blood of Ci/piinuH hrama completely 

 parallel in their form the above-described anucbiform masses found on the gills of 

 the fish, and are differentiated among themselves in the same way as the gill forms 

 [t. c, they are either granular or granule-free]. Their movements are, on account 

 of their small size, difticult to observe. 



