46 ORIGINAL ARTICLES. 



the infected specimens. All, however, that have come under my notice 

 were large females, and I have never seen a single Sphaerularia in a 

 worker or a male. 



The worms lie free in the cavity of the body, and are somewhat 

 curled up. The largest number of full-grown females which I ever 

 found in a single bee was eleven, but the usual numbers were from five 

 to eight. The two infected specimens of B.pratorum, however, contained 

 only one specimen of the parasite apiece. 



Anatomy of Sph. bombi. 



FEMALE. 



Von Siebold was quite correct in asserting that all the specimens ob- 

 served by him were females; the males being, as mentioned below, very 

 much smaller in size, and quite different inform and appearance. The full- 

 grown females, as they are met with in May, June, and July, are nearly 

 an inch long, more or less curled up, white in colour, sometimes opaque, 

 sometimes more or less transparent, and of equal thickness from one end 

 to the other, being everywhere about J^th of an inch in diameter. The 

 whole surface is covered with button- like projections, PI. 1, Fig. 1, from 

 which the very appropriate generic name is derived. These buttons are 

 situated at equal distances from one another, and are of more or less 

 equal size ; each one is from T ^^ths to y^y ^ ths of an inch in diameter, 

 and the intermediate spaces are a little smaller. There are, therefore, 

 10 longitudinal, and about 80 transverse rows, making, in all, about 800 

 of these projections ; and each of them projects from y^o^ ns ^° T(J 6 oo^ ns 

 of an inch above the general surface of the body. 



Generally these spherules are nearly as transparent as the rest of 

 the skin ; here and there, however, some of them are rendered quite 

 opaque by the presence of innumerable, minute, greenish, elliptic bodies, 

 each about ^oo^ 1 °f an ^h * n length, by Too"oo^ n °f an mcn ^ n 

 breadth. These darkened spherules are comparatively few in number, 

 only one here and there being affected in this manner, except round the 

 vulva, where from eleven to fourteen were generally in this condition. 

 No other Nematoid worms have wart-like projections so much developed ; 

 many species, however, have, on particular parts, and especially in the 

 male sex, buttons, much less than, but doubtless homologous with, 

 those which are so much developed in Sphgerularia, and have suggested 

 for it a name so characteristic. Leon Dufour and Siebold considered the 

 Sphserulari from the different sorts of humble bees, as belonging to 

 one species; and all the specimens which have come under my notice 

 have been very similar to one another, and have presented no differences 

 of specific value. One specimen, however, was a little narrower than 

 the rest, and more transparent; the buttons, also, were smaller than 

 usual, and the body tapered a little towards the end which contains the 

 vulva. 



In turning to the internal anatomy, one can, with reference to some 

 highly important organs, and systems of organs, only parody Van Troil's 





