THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. KE 
and Coccidia), which it is necessary, at least until further information is obtained, 
to regard as distinct. 
He further says that he fails to see any homology between the 
myxosporidian capsule and the falciform bodies of the gregarine spore. 
Giard (see p. 170) suggests that the relation of the ‘‘psorosperms” to 
the Gregarines may be parasitic and not genetic; Lithocystis schneidert 
is regarded as a vegetable. 
In 1879 Leuckart! recorded his opinion against the gregarine nature 
of the Myxosporidia, remarking that: 
It appears, however, scarcely permissible at present to unite these psorosperm-sacs 
with the Gregarines, not merely because they lack the shell-wall which surrounds 
the gregarine spore (Pseudonavicellen-Behalter) but still more because the formation 
of the psorosperms begins at a time when the organism is still more or less removed 
from its maximum size, and such formation progresses thence during the whole of 
the subsequent existence. What is divided with the Gregarines into tjyo successive 
phases falls with the psorosperm-sacs into one. 
In several papers? Gabriel refers the ‘‘psorosperms” to the Myxomy- 
cetes. In his myxosporidian paper? (upon Myxidium lieberkiihnit) he 
says that— 
The Myxosporidia can not be Gregarines, as they lack (1) the definite typical form, 
(2) the differentiated membrane, (3) the nucleus, and (4) the monosporogenetic 
centers. Further, they possess’ the following nongregarine characters: (5) the 
manifold peculiar protoplasmic movements, (6) the ‘‘thread-drawing” substance, 
(7) yellow pigment, (8) vacuoles, (9) polysporogenetic centers. The importance of 
characters 1 to 4 demands the separation of the Myxosporidia from the gregarine 
phylum. Further, while Lieberkiihn’s opinion that a membrane is not essential to 
a Gregarine might be admitted, the essentiality of a nucleus is less easily waived, 
and the fact remains that no Gregarine is known which simultaneously lacks both 
of these structures. Little satisfactory when considered alone, characters 5 to 9 
confirm the myxomycetoid affinities of the Myxosporidia, as they are analogous to 
_ many exclusively myxomycetoid characters. Moreover, in Lieberkiihn’s time many 
subsequently discovered myxosporidioid, myxomycetous, and mycetozoan characters 
were still unknown. 
Too much stress should not be laid upon the absence of pigment in gregarine 
species, although it is not concealed that the presence of pigment (yellow, brownish 
yellow, dark brown, blackish brown) is highly characteristic of the Myxomycetes. 
The Myxosporidia are, therefore, to be annexed (not subordinated) to the Myxomy- 
eetes. The fact that they do not display typical myxomycete characters must not, 
however, be ignored. Though nearly allied to the same phylum, they are phyloge- 
netically of more recent date and represent a small, sharply defined group, interme- 
diate between the Myxomycetes and the Gregarines, originating by progressive 
adaptation to restricted and new life conditions. 
1 Die Parasiten des Menschen, 2 ed., p. 245. 
2Tagebl. d. 51 Versamml. d. deutsch. Naturf. u. Aerzte, 1878, pp. 51, 52; Tagebl. 
d. 53 Versammil. etc., 1880, pp. 82, 83; extracts, criticism, etc., Zool. Anzeiger, 1880, 
ml, p.572; Zoolog. Jahresber., 1880, 1, p.161; Journ. Roy. Micr. Soc. London, 1882, 0, 
pp. 358, 359. 
3 Jaliresber. schles. Ges. vaterl. Cultur f. d. J. 1879, Lv11, pp. 188-195.. 
FC 92 T 
