THE MYXOSPORIDIA, OR PSOROSPERMS OF FISHES. 205 



thrown out of the water. The abnormal individuals never included 

 egg-bearing females. 



This, Henneguy and Thelohan think, recalls the asjiect of Crustacea 

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

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

 think, another case of " parasitic castration." 



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

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

 nation, no sign whatever of infection. 



33. Thelohauia macrocystis Gurley, 1893. PI. 12, tig. 3. 



(Sarcosporidian o£ Pakeriioaetes varians Garbini/ 1891, Rend. Real. Accad. Liu- 

 cei Roma, vii, Sem. 1, pp. 151, 152 with fig. ; myxosporidian of ibid., Thdlo- 

 han and Henneguy, 1892, Compt. Rend, liebdom. Soc. Biol. Paris, iv, p. 586.) 



Thelohaniamacrocjjstis, Bull. U. S. Fish Com. lor 1891, xi, p. 410; ib., Braun, 

 1894, Centralbl. f. Bakt. u. Parasiteukde, xv, p. 86. 



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

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

 rounded vesicles. 



S2)ores. — Eight in number, pyriform, shell difficultly stamable, col- 

 oring only in a 0-5 per cent boiling solution of eosinj spores easily 

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

 round "nucleus" more clear and transparent than the surrounding 

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

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

 culty discernible; probably these represent more advanced stages of 

 the same parasite. Garbini failed to lind 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 muscles of Palcemonetes 

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



Nature. — This species has much analogy with Thelohania octospora, 

 but presents some noteworthy differences that warrant its specific sep- 

 aration. 



Ordo II. Phsenocystes Gurley, 1893. 



Etymology: (pfio^^, I appear; kvotiq, capsule. 



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

 Bakt. n. Parasiteukde, xv, p. 86. 



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, Myxoholidoi. 



1 First described in Garbini's "lutorno ad ua nuovo microorganismo p.arassita del 

 Palcemonetes varians (title only); Atti Real. Accad. Lincei Roma, 1890, vi, p. 526; 

 unpublished. 



■^Except Myxobolus U7iicaj)8ulatus and M. 2ii>'ifonn,is, This qualification is omitted 

 by Braun. 



