THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. 173 
3 or 4 together into irregular clumps. Many such clumps had no sur- 
rounding membrane, but some showed such a membrane containing 
several corpuscles. The features of the latter bodies were plainly dis- 
cernible through the enveloping membrane. The corpuscles at this 
stage are unsSplit, the valves being united for their whole length, form- 
ing a lenticular corpuscle. Further, similar cysts were seen which 
showed no developed corpuscles, but only large granules. Finally, a 
number of separated valves may be seen. From these facts Miiller 
concludes that the corpuscles in question develop several in a cyst, are 
set free unsplit, subsequently the valves separate, at first partially, at 
last probably entirely, and then perhaps the cycle is repeated. 
Habitat.—Air bladder of Gadus morrhua (= callarias), cod. 
Nature.—Robin includes it among the “ psorosperms.” 
Dr. L. Wittmack ! refers to this as a “ psorosperm.” 
Concerning this form Prof. Biitschli? says: 
It appears to me quite questionable whether these psorospermiform corpuscles 
of the air bladder of Gadus callarias are to be referred to the Myxosporidia proper or 
to the Coccidia. Their structure appears to approximate itself rather to the latter; 
especially in the absence of the polar capsules so characteristic of the Myxosporidia. 
I can see no myxosporidian structure in it, and have, therefore, 
omitted it from the subclass. 
Effects —Mucous membrane of the air bladder red and swollen, infil- 
trated by the parasitic mass. Tail unusually thin and shrunken, the 
soft parts being markedly atrophied, the muscular tissue having dis- 
appeared. Further observation must determine the constaney and 
causality of relation between the two conditions. Such atrophy is 
apparently not rare in Gadus, as the fishermen at Bohuslin knew the 
disease and informed Miiller that it rendered the fish unfit for food. 
Miiller says that the difference between this form and the psoro- 
sperms of fresh-water fishes is as great as that between different 
genera of animals. 
Atrophy of tail of Merlangus merlangus.3 
The following observation probably can not be better placed than as 
an appendix to the similar disease of G. morrhua just described. Among 
the Mediterranean fishes collected by Mr. Peters, Miiller and Retzius 
noted a Gadus merlangus affected with complete atrophy of the tail 
muscles, the tail being composed of nothing but skin and bone—not the 
slightest trace of muscular tissue remaining. .The junction of the nor- 
mal and atrophied tissue was abrupt and was situated at the root of 
thetail. Unfortunately, the air bladder had not been preserved. 
1 Beitriige zur Fischerei-Statistik d. deutsch. Reichs, 1875, p. 191, footnote. 
2 Bronn’s Thier-Reich, 1882, 1, p. 591, footnote. 
§Miiller and Retzius, 1842, Miiller’s Archiv., p. 198; see also p. 172. 
