THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. 205 



thrown out of the water. The abnormal individuals never included 

 e^g-bearing females. 



Tliis, Henneguy and Thelohau think, recalls the aspect of Crustacea 

 infected by Myxosporidia. They have also never seen egg-bearing 

 females among the infected Palajmons. Perhaps we have here, they 

 think, another case of "parasitic castration." 



Infection experiments. — iV Caradina desmuresti fed for 71 days with 

 the muscles of an infected Grangon, showed, on the most careful exami- 

 nation, no sign whatever of infection. 

 33. Thelohauia macrocystis Gurlej', 1893. PI. 12, Hg. 3. 



(Sarcosporidiiiu of Pdl'wmonete.'^ varians Garbini,' 1891, Rend. Real. Accad. Lin- 



cei Roma, vii, Sem. 1, pp. 151, 152 with fig. ; niyxosporidian of ibid., Th(Slo- 



lian and Henneguy, 1892, Compt. Rend, liebdom. Soc. Jiiol. Paris, iv, p. 586.) 



Thelohania macrocijsfis, Bull. U. S. Fish Com. for 1891, xi, p. 410; ib., Braun, 



1891, Centralbl. f. Bakt. u. Parasitenkde, xv, p. 86. 



SporopJiorous vesicle. — Elongate fusiform. This is the principal char- 

 acter distinguishing this species from T. octospora, which has perfectly 

 rounded vesicles. 



Spores. — Eight in number, pyriform, shell diliicultly stainable, col- 

 oring only in a 0-5 per cent 'boiling solution of eosiu; spores easily 

 stainable by Gram's method; in the larger posterior end a distinct 

 round ''nucleus" more clear and transjiarent than the surrounding 

 sporophism. Together with these forms are others with a thicker and 

 more difficultly stainable shell, within which 8 corpuscles are with diffi- 

 culty discernible; jirobably these represent more advanced stages of 

 the same j^arasite. Garbini failed to tind other developmental stages 

 corresponding to those found by Henneguy in T. octospora. Inocula- 

 tion of healthy animals proved a failure. 



Habitat. — Occurring in great numbers in the nmscles of Palccmonetes 

 varians (prawn) from the Mincio in the neighborhood of Verona. 



]\^atiire. — This species has much analogy with Thelohania octospora, 

 but presents some noteworthy differences that warrant its specific sep- 

 aration. 



Ordo II. Phaenocystes Gurley, 1893. 



Etymology: <>fur6;, I appear; /cuarff, capsule. 



Bull. IJ. S. Fish Coui. for 1891, xi, pp. 409, 410; ib., Braun, 1894, Centralbl. f. 

 Bakt. u. Parasitenkdo, xv, p. 8(3. 



Definition. — Myxosporidia, in which the pansporoblast produces few 

 (1 or 2) spores; the latter relatively large, with distinct symmetry and 

 2 or more capsules ;^ type family, MyxohoUdw. 



•First described in Garbini's "Intorno ad tin nuovo microorganismo parassita del 

 Palu'vionclca varians (title only); AUi Real. Accad. liincei Roma, 1890, vr, p. 526; 

 unpublished. 



•^Except Myxobolas unica^iHulatus and M. piriformia. This (lualitieatiou is omitted 

 by Braun. 



