282 REPORT OF THE CO^BHSSIONER OP FISH AND FISHERIES. 

 Concerning tliis species Biitschli says: 



Ball)iniu has observed cysts in the body cavity of .a butterfly (Pyralis vu-idinua) 

 Tvhich were filled with corpuscles possessing a structure similar to that of tlie myx- 

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

 belongs to the Myxosporidia. 



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

 cult for me to tliink otherwise. 



VIII. SPH^ROMYXA Thc-lohan, 1892. 



Etymology not given. 



Conipt. Rend. Acad. Sci. Paris, cxv, p. 1093; ih., Br.aun, 1893, Centralbl. f. Batt. 

 u. Parasitenkde, xv, p. 737. 



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

 S. balbianii. 



After several vain attempts to draw nj) a satisfactory generic defini- 

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

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

 delimitation. 

 99. Sphseromyxa balbianii Th^lohan, 1892. 



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

 Bakt. n. Parasitenkde, xv, p. 738. 



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

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

 variable part of tlie bladder and escaping with the bile; yellowish or 

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

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

 Under the microscope the myxosporidium shows absolutely exceptional 

 characters. Ectoplasm forming a clear, homogeneous zone, presentnig 

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

 numerous spores. 



ASporc. — liesembling that oi Myxidium lieberJmhniij elongate, slightly 

 sw^ollen at middle; extremities abruptly truncate, cut squarely off, so 

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

 16 ii; "breadth" [1J 5 //, Shell bivalve, finely striate, parallel to the 

 longer axis. Capsules 2, one at each "extremity," their axes obli<}ue 

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

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

 short (average length 15//) cone, the diameter of whose base nearly 

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

 iodine water, potassium hydrate, sulphuric acid, etc. The mode of coil- 

 ing is equally i)eculiar, 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 "(Th^lohan's 

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



Habitat. — Free in the gall bladder of Onns tricirratus and 0. macu- 

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

 Roscoff. 



