282 REPORT OF THE COMMISSIONER OF FISH AND FISHERIES. 



Concerning tbis species Biitsclili says : 



Balbiaui lias observed cysts in the body cavity of a butterfly (Pyralis viridiana) 

 which were tilled with corpuscles possessing a structure similar to that of the myx- 

 osporidian spore. The observation is, however, not sufdcient to demonstrate that it 

 belongs to the Myxosporidia. 



Th^lohan and Henneguy regard it asamyxosporidian, and it is diffi- 

 cult for me to think otherwise. 



VIII. SPH^ROMYXA Thclohan, 1892. 



Etymology not given. 



Compt. Rend. Acad. Sci. Paris, cxv, p. 1093; Ih., Braun, 1893, Centralbl. f. Batt. 

 u. Parasitenlide, xv, p. 737. 



Definition. — Characters to be inferred from those of the type species, 

 8. balhianii. 



After several vain attempts to draw np a satisfactory generic defini- 

 tion as between this genus and Cystodiscus, I have concluded that at 

 present there are not in the record sufficient data for their accurate 

 delimitation. 

 99. Sphaeromyxa balbiaiiii Thelohan, 1892. 



Compt. Rend. Acad. Sci. Paris, cxv, pp. 1091-3; t&., Braun, 1893, Centralbl. f. 

 Bakt. u. Parasitenkde, xv, p. 738. 



Myxosporidium. — Generally visible to the naked eye as a small 

 opaque, more or less regular, usually subspherical mass, occupying a 

 variable i)art of the bladder and escaping with the bile ; yellowisli or 

 greenish yellow, of a relatively firm consistence, permitting of handling. 

 Attempts at teasing render evident the presence of a thin membrane. 

 Under the microscope the myxosporidium shows absolutely exceptional 

 characters. Ectoplasm forming a clear, homogeneous zone, presenting 

 in sections a very clear striation. Endoplasm more granular, inclosing 

 numerous spores. 



ISjwre. — Eesembling that of MyxkUum lieberlcuhnii, elongate, slightly 

 swollen at middle; extremities abruptly truncate, cub squarely off, so 

 to speak, so as to present very sharp " lateral " angles ; " length " [ ?] 13 to 

 16 /.I', "breadth" [?J 5 /<. Shell bivalve, finely striate, parallel to the 

 longer axis. Capsules 2, one at each "extremity," their axes oblique 

 and oppositely directed with reference to the longer [transverse'?] diam. 

 eter of the spore. Filament very i:)eculiar, forming a relatively very 

 short (average length 1.5/0 cone, the diameter of whose base nearly 

 equals the breadth of the extremity of the spore. Exit produced by 

 iodine water, potas'jium hydrate, sulphuric acid, etc. The mode of coil- 

 ing is equally peculiar, the axis of the coil being perpendicular to the 

 long axis of the capsule. Sporoplasm forming a single mass, destitute 

 of an iodinophile vacuole; nuclei, 2; the pericornual nuclei (Thelohan's 

 "nuclei of the capsulogenous cellule") are also present. 



Habitat. — Free in the gall bladder of Onus tricirmtus and 0. macu- 

 latus {=Motella tricirrata and M. maculata)-, very common, especially at 

 Roscoff. 



