THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. 211 



Spore. — or the form and size of Chloromyxum flnjardiui. Capsule only 

 1, situated on one side of the anterior end, obliquely directed. 

 Rahifaf. — On Labeo niloUcus from tlie Nile. 



35. Myxoboius piriformis Tli<;]olian, 1892. Phite 13, fig. 3 {pars), 4 {pars) ■ ; pi. 18. 

 (Peorosperins of the tench {pars) Balbiani, 1883, Joum. de Microgr., vir, pp. 

 197-198, fig. 66 &, c, ? d-f; ib. {pars) Balbiani, 1884, L6gons sur les Sporo- 

 zoaires, pp. 125-6, fig. 47 b, c, ? d-f] pi. 4, figs. 1, 2, 8A {pars) \ ? 3B, C ; 

 ? ih. {j}ars) Pfeiffer, 1890, Die Protozoen als Kraulieitserrcger, 1 ed., pp. 

 48,55, fig. 16; ? ih. {pars) 1891, 2 ed., p. 132, fig. 56. 

 ITyxoioliis piriformis, Bull. Soc. pliiloiuat. Paris, iv, p. 177; ih., Gurley, 1893, 

 Bull. U. S. Fish Com. for 1891, xi, p. 414; ih., Brauu, 1893, Centralbl. f. 

 Bakt. u. Parasitenkde, xiv, p. 739; ib., Braun, 1894, Centralbl. f. Bakt. u. 

 Parasitenkde, xv, p. 86. 

 Synonymy. — M. Thelohan informs me (letter, 1893) that : 



M. piriformis has very probably been seen by Reniak, although hia figures and his 

 descriptions do not prove it absolutely (pi. 5, fig. 5). He does not figure the polar 

 cajisules, but his figures almost certainly belong to the species in question. 



Fig. 8 represents 2 spores from the kidney- of the tench, which I do not know to 

 what sj)ecies to approximate. The presence of 2 capsules separates them from M. 

 piriformis. The form of its spores and the small size of the capsules do not i)ermit 

 of its apiiroximation to any of the forms that I have encountered. 



The typical spore of M. piriformis contains but 1 polar capsule. As in all species, 

 one can find monstrous spores which inclose 2 capsules, but tbey have seemed to me 

 very rare. This si^ecies is often accompanied, above all in the spleen of the tench, 

 by M. ellipsoides. Almost all the spores with 2 capsules, represented by the authors, 

 belong, I believe, to the sjjores, more or less monstrous, of this last species. 



Balbiani considered M. piriformis a degraded form of M. ellipsoides. I have been 

 able to convince myself that this mode of view is not correct. It is a species abso- 

 lutely distinct and well characterized, as I have been able to determine by numerous 

 observations. 



After reading the above, I restudied the synonymy as between this 

 species and M. hrachycystis, and can not but feel that all of Remak's 

 figures are referable to 1 species, which probably is, as Thelohan thinks 

 and contrary to my former opinion,^ distinct from his M. viriformis. 

 The following are the conclusions at which I have arrived : 



(a) Remak's figures are referable to 1 species. His fig. 8 (referred to 

 in the second paragraph of the above quotation) is not from the kidney 

 but from the spleen. There appears to me to be, especially in view of 

 Remak's statements which tend to show that he considered the question 

 carefully, no ground for a separation between these 2 developed spores 



1 The figures in the rows on Balbiani's plate iv, fig. 3, are numbered in order from 

 left to right, in the reproduction of it on pi. 13, fig. 3. The proper specific refer- 

 ences of some of the figures of groups 3 and 4, on that plate, are dubious. The fol- 

 lowing is about all that can be safely said at present : 



Indeterminate: Figs. 3 B, C; M-f. (either M. jnriformis or M. ellipsoides). 



Mijxoholus piriformis : Figs. 3 A, Nos. 1, 2, 6; ib, c. 



Myxoboius ellipsoides : Figs. 3 A, Nos. 3, 4, 5, 7 (the last with some certainty, the 

 rest iDrobably, "abnormal" spores) ; 4a. 



'^ These spores (Remak's tig. 8) are from the spleen. 



" Bull. U. S. Fish Com. for 1891, xi, p. 409, second footnote, where it is stated that 

 1 Myxoboius species x^ossesses, perhaps inconstantly, a single caj)sule. At that time I 

 inclined to fuse M. brachyoyatis with M. piriforviit. 



