THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. 243 
Spore.—Always 2, oval, with 2 capsules situated “at the superior 
border in the transverse diameter.” Perugia did not see the extrusion 
of the filaments under the action of reagents. He adds that he has 
convinced himself of the accuracy of Thélohan’s opinion as to the 
vacuolice nature of Biitschli’s *‘*nucleus” and also of that of Thélohan’s 
observations upon the nuclei of the spore. 
Habitat.—Gall-bladder of Merlucius merlucius (= esculentus, = vul- 
garis), hake, collected August 13, 1890. 
Remarks (see also p. 275).—This is arather peculiar species, and the 
generic reference is provisional. As indicated elsewhere, gall-bladder 
species of Myxobolus are so rare that this habitat is a caution-mark as 
to the generic reference of imperfectly described forms. The present 
generic reference is made provisionally and very doubtfully upon Peru- 
gia’s assertion of the presence of an iodinophile vacuole. Finally, 
attention may be directed to Perugia’s figure 9 (pl. 29, fig. 2), which 
differs entirely from the others. 
65. Myxobolus ? sp. incert. 
Psorosperms of Gobio jluviatilis Lieberkiihn, Miiller’s Archiy., pp. 353-4; 1b., 
Lieberkiihn, 1854, Bull. Acad. Roy. Belg., xxi, pt. 2, pp. 21-2; ? myxo- 
sporidian of kidney of G. fluviatilis Thélohan, 1890, Annal. de Microgr., 
II, p. 198; ib., of Gobius [error] Pfeiffer, 1890, Die Protozoen als Krank- 
heitserreger, 1 ed., p. 49; ib., Pfeiffer, 1891, ibid, 2 ed., p. 134. 
Cyst.—Nearly spherical, about 0.22 mm. in diameter; contents, ‘ pso- 
rosperms,” empty shells of the same, “free nuclei” of the same, and 
amceboid bodies with amceboid movements. 
Myxosporidium.—The above and below mentioned ameeboid bodies 
in all probability represent the earliest stages. 
Spore.—Untailed. Lieberkiihn repeatedly saw spores contract to an 
hour-glass shape and extrude an amceboid body, which formed blunt 
processes, and moved slowly over the field, the movements continuing 
for a long time; amosboid bodies diaphanous, destitute of granules 
and of apparent structure, usually invisible within the spore, but some- 
times plainly seen; size, that of a colorless blood corpuscle. 
Habiitat.——In the kidney and eneysted in body cavity between the 
kidney and the air-bladder of Gobio gobio L. 
Remarks.—The habitat and the “eneysted” condition of this form 
imply Myxobolus affinities. 
66. Myxobolus ? sp. incert. 
Psorosperms of Perca fluviatilis, Miller, 1841, pp. 481, 490; ib. Robin, 1853, Hist. 
Nat. des Végét. Parasites, p. 296; ib. Lieberkiihn, 1854, Miiller’s Archiv., 
p. 365; ib. Bessels, 1867, Tagebl. d. 41 Versamml. d. deutsch, Naturf. u. 
Aerzte, pp. 71-72. 
Cyst mentioned but not described by Lieberkiihn; myxosporidium 
unknown. 
Spore.—Untailed. Bessels observed the extrusion of the filaments 
as a result of 8 hours’ immersion in glycerin. 
Habitat.—In May and June encysted in the skin of Perca fluviatilis 
