322 WILLTAM A. HASWELL. 



forwards and inwards, and then beuds round, following the 

 line of the anterior border of the ovary, and runs backwards 

 to open near its fellow of the opposite side into the anterior 

 part of the space (uterus) containing the large mature ovum. 

 It is a comparatively wide tube, ciliated internally, with 

 thick walls, having a granular appearance, due evidently to 

 the presence of numerous minute bright granules or vesicles. 

 In close relation to it is a glandular body [vit.), of varying 

 size, consisting of finely granular material, with a large nu- 

 cleus here and there, but without cell limits and without 

 lumen. When well developed this body fills up a good deal 

 of the space between the wall of the body, the alimentary 

 canal, and the lateral paired portion of the ovary. It appears 

 to terminate behind in close relation to the corresponding 

 oviduct. I am in doubt whether these bodies are to be looked 

 upon as shell glands or as vitellaria. I think the latter view 

 is the more probable, and accordingly I have provisionally 

 given them that name. If they have this function the shell 

 must be secreted either by the cells of the follicle or by the 

 wall of the oviduct. 



When a ripe ovum has become discharged its place is 

 taken by the next in size. This must receive accessions of 

 vitelline matter with great rapidity, as the median ovum in 

 mature animals is nearly always greatly larger than the next 

 in point of size. From their arrangement it is evident that 

 the ripe ova are derived from the right and left sides alter- 

 nately. The shrivelled follicle of the ovum which has been 

 last discharged is sometimes to be found pushed on one side 

 by the ovum which has succeeded. 



Foettinger's account^ of the female reproductive organs in 

 Histriobdella differs from the above in several important 

 points. The structure of the ovaries is evidently similar in 

 all essential respects, except that in Histriobdella there is 

 not, as in Stratiodrilus, a single ovum greatly predomi- 

 nating in size over the rest — several ova of approximately 

 equal size occurring together ; and that in the former the 



' L. c, p. 473. 



