THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. 239 



56. Myxobolus sp. incert. PI. 28, fig. 4. 

 Cyst and myxosporidium unknown. 



Spore. — Broadly elliptic; length, 14 /i,- breadth, 10 /.q thickness, 5 yu; 

 shell bivalve; valves equally convex; ridge index about 0-25. Cap- 

 sules 2, equal; capsular index not quite O'oO. Sporoplasm showing a 

 clear, round space, witliout doubt the vacuole. 



Habitat. — Body cavity of Garassius Garassius L. (goldfish), from Ger- 

 many. 



Remarls. — For this species I am indebted to Dr. C. W. Stiles, who 

 mounted the spores in Leipsic. The exact locality whence the host 

 came is unknown. The si^ecimen was mounted unstained in Farrant's 

 solution. For this reason the vacuole could not be stained or the 

 nuclei be determined. 



57. Myxobol'js ? obesus Gurley, 1893. Pi. 28, fig. 7. 



(Psorosperm of the "Ablette," Balbiani, 1883, .Journ. rle Microgr., vir, p. 203, 

 fig. 43; ib. Balhiaui, 1884, LdQons sur les Sporozoaires, p. 133, fig. 39.) 



Myxoholua ohesnn, iJiill. U. S. Fish Com. lor 1891, xi, p. 415; ib. of Albunms 

 lucidus^ Braiin, 1894^ Centralbl. f. Bakt. u. Parasiteiikde, xv, p. 87. 



No description. 



Habitat. — On Alburnus alburnus L. 



58. Myxobolus cycloides Gurley, 1893. PL 28, fig. 5. 



CPsorosperms of Cyprinus rutilus, Miiller, 1841, Miiller's Archiv., pp. 481, 

 486, pi. 16, fig. id-fi; ib.,^ Creplin, 1842, Wiegraanu's Archiv. f. Natur- 

 gcsch., I, p. 63 (footnote); i&., MiilJer, 1843, Rayer's Archiv. de. M<^.d 

 comp., I, p. 226, pi. 9, i\g.id-fj; io., Rayer, 1843, ibid., p. 269; ib., {pars) 

 Robiu, 1853, Hist. Nat. V^get. Parasites, p. 299, pi. 14, fig. 6.) 



Myxobolus cycloides, Bull. U. S. Fish Com. for 1891, xi, p. 415; ib., Brauu, Cen- 

 tralbl. f. Bakt. u. Parasiteukdc, xv, p. 87. 



Gijst. — Xot described. Creplin states that the membrane is very 

 delicate and that it is "dissolved" by water. 



Myxosporidium unknown. 



t^pore. — Snbcircular-ovate or broadly rounded-elliptic, resembling M. 

 cireiilaris; length, 12 /i (0-0054'"). 



Habitat. — Encysted, most frequently on inner surface of ojiercle and 

 particularly on the iJseudobranchiae {NcbeHkiemen) of Leuciscm rutilus 

 from German rivers. Disease of very frequent occurrence, principally 

 in May and June. Crei>lin's specimens were taken May 8, 1835, and 

 January 31, 1839. 



59. Myxobolus sp. incert. 



Myxosporidiau spore of Gardon, Th^lohan, 1889, Compt. Rend. Acad. Sci. Paris, 

 cix, p. 921. 



iSpore. — Vacuole present; maximum number of nuclei, 3. 



Habitat.— Oil the " Gardon.''^ At present this form is entirely indeter- 

 minate, as M. Thelohau informs me (letter, 1893) that Gardon is applied 

 indiscriminately to both Leuciscm rutilus and L. erythrophthalmus. 



1 The question between the two specific names is merely that of the advisability 

 of the use of a specific name identical with the generic. 

 * Creplin compares his form to Miiller's, iig. id. 



