COLLINGE : 0\ THE ANATOMY OF THE VITRINA IRRADIANS. 67 



granules (Fig. 6a) and the spherieal ones (Fig. 6r), were ruptured, and 

 it was clearly evident that they contained some substance very like 

 protoplasm, for it readily stained with magenta (50% Al. sol.), 

 Grenacher's carmine, and other stains, whilst a denser portion (? a 

 nucleus) took the stain much more readily. Treated with dilute 

 hydrochloric acid (5 and 10 per cent.), all the granules excepting the 

 largest of the spherical ones, were disolved, these latter remaining 

 unchanged even when treated with strong hydrochloric acid. 



The question naturally arises, what is the function of the spicule 

 and granules?: to which at present, I am unable to give any satis- 

 factory answer. We know that no calcareous matter is required for 

 the spermatozoa, and it seems out of the question to suppose that 

 they are transferred from here to the dart-sac, nor is it any more likely 

 that they are in any way connected with the formation of the 

 spermatophore. It is important to point out that in the specimens in 

 which these bodies were either present in only small numbers or 

 absent altogether from the kalk-sac, large numbers of the spherical 

 granules only were found in the receptaculum seminis. This fact 

 would lead one to suppose that they had been transferred with the 

 spermatozoa. 



When examining a specimen of Nilgiria tranqneharica, in which 

 the spermatophore was only partially formed, I thought that possibly 

 the spicule found in liatnadinpia might also be a spermatophore in 

 the process of formation, but a more careful examination of a second 

 example, the one figured, convinced me that this is not so. The two 

 found were present in fully matured animals measuring (in alcohol) 

 72 and 76 millim. in length, respectively, further in both cases the 

 spicule was firmly implanted at its basal end in the substance of the 

 wall of the kalk-sac, and only by very careful teasing was it separated 

 from the surrounding tissue. 



The retractor muscle of the penis is inserted into the apical 

 portion of the diverticulum (Fig. 2, r. m.). The vas deferens is long, 

 and in life lies upon the vagina and free-oviduct. The dart-sac and 

 gland (Fig. 2, d.s., d.<jl.) form a large organ lying upon the floor of the 

 body cavity, the distal end of the gland extending to the extreme 

 posterior portion. In some cases it is recurved forward owing to its 

 great length. Usually it exhibits the sharp bend shown in Fig. 2, 

 but this is not always present, it may be almost straight. Attached 

 to the distal end is a short muscle, which arises from the ventral wall 

 of the body cavity. 



In none of the specimens dissected was any calcareous dart found, 

 but at the distal end of the somewhat baggy dart-sac, a blunt, fleshy 



