994 REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 
conjugation. And still further, in some individuals the filaments 
instead of lying along the borders ofthe valves, extend themselves in the 
direction of the axis of the body, and, reuniting themselves for a variable 
distance, conmitute the simple or double caudal prolongation that 
Miiller and other observers describe as a specific character of certain 
psorosperms. (See also p. 207.) 
Concerning these, Biitschli! states that he could find no evidence 
whatever of the existence of such ribbons, either in the whole spore or 
in the separated valves. He seems to think that such ribbons are an 
illusion due to an abnormal extrusion of the capsular filaments. 
Thélohan’s observations seem to throw some light upon this diserep- 
ancy. This observer? says that he has never seen them except in the 
present species. They are frequently absent, yet the spores split open 
perfectly. Having found all possible transitions between the ribboned 
spores and spores evidently monstrous and abnormal, he regards the 
ribbons as structures, accidental rather than fundamental and neces- 
sary to the development of the spore. 
Habditat.—Thélohan gives this as the branchiz, air bladder, liver, 
intestine, and spleen (last fide letter to author, 1893) of Tinea tinea L. 
(tench). Balbiani says the Myxosporidia are always confined to the 
short anterior portion of the air bladder. 
Speaking collectively of a poorly delineated and very probably multi. 
specific group of forms, Pfeiffer says that perfectly developed forms 
occur on the branchie and in the air bladder, this stage of development 
being possibly connected with an abundance of oxygen. In the gall 
bladder incompletely developed forms occur, with 3, 1, or no capsules; 
also entirely undeveloped forms, destitute of a bivalve shell, compara- 
ble to the Microsporidia or to the pseudo-navicelizw found in Lumbricus. 
Transition forms to the Coccidia also occur. Possibly (from Pfeiffer’s 
figure) M. ellipsoides may also occur in the air bladder or gall bladder. 
Effects —The Myxosporidia do not confine themselves to existing 
cavities. Thus, in the kidney of Tinca tinca, Thélohan (1890, p. 200) 
has seen the tissue of the organ invaded while the tubes remained free 
(see also the above description of changes produced in the structure 
of the air bladder by the myxosporidium found in that organ). 
50. Myxobolus ? sp.incert. Pl. 22, fig. 4. 
Psorosperms of Cyprinus leuciscus, Miiller, 1841, Miiller’s Archiv., p. 486; %b., 
Dujardin, 1845, Hist. Nat. des Helminthes, p. 644; ib., Leuckart, 1852, 
Archiv. f. physiol. Heilkde, x1, p. 436, fig. 2le, d; ib., Robin, 1853, Hist. 
Nat. des Végét. Parasites, p. 299. 
Synonymy.—This is little more than a collection of references to 
spores found on “Cyprinus leuciscus.” Robin’s mention is, however, 
certainly the same as Miiller’s. 
Cyst and myxosporidium unknown. 
1Ztschr. f. wiss. Zool., 1881, xxxv, p. 633; Bronn’s Thier—Reich, 1882, 1, p. 598. 
2Compt Rend, Acad. Sci. Paris, 1889, c1x, pp. 920-1, 
