The Non-Marine Mollusca of Portuguese East Africa. 205 



an inner division with six to nine small cusps or denticles, a middle division 

 with about eighteen or twenty narrow denticles, like the teeth of a comb, 

 and an outer more delicate portion without any denticles. This outer 

 portion is not developed at the hind end of the radula, the teeth in the last 

 thirty-five being without it. The transverse rows are -03 mm. apart ; 

 and as the bases of the teeth are about five times this length, the successive 

 rows overlap to a great extent. In about seventy of the rows towards 

 the hind end of the radula the thicker parts of the teeth are coloured 

 brown. 



In its radula this species bears a close resemblance to those of the other 

 South African species of the subgenus Ligatella, which seem to have very 

 similar radulae, differing from one another and from the present form only 

 in small details. The radula of Pomatias elegans is of a slightly difierent 

 type, but that of the Mediterranean species, P. melitensis, differs but little 

 from those of this African group. 



The radula-sac projects a considerable distance from the hind end of 

 the buccal mass, and is bent upwards and forwards (PI. VI, fig. 5). The 

 salivary glands are long and narrow ; but they are much convoluted and 

 twisted, so that they do not extend far back. The oesophagus is narrow 

 except near the salivary glands, where it is slightly swollen. It opens into 

 the stomach in about the middle of this organ, which is long and curved. 

 The posterior part of the stomach, which ends blindly, has a furrow running 

 along its convex surface. The intestine arises from the opposite end, and 

 is folded upon itself twice or thrice before passing forward to the rectum, as 

 shown in the figure. The anus is situated on the right side of the mantle- 

 cavity towards the front end. 



Reproductive organs.— Oi the three specimens examined one was a male 

 and two were females. The male genital ducts are shown in fig. 6. The 

 upper part of the sperm-duct is convoluted and somewhat swollen. Further 

 forwards it passes into the rather large, oval, prostatic gland, the posterior 

 part of which is pale grey, and the anterior white. The external layer of the 

 gland is formed of small papillae, those on the anterior white portion being 

 best developed. In front of the prostatic gland the vas deferens is very 

 slender. It passes into the large muscular penis, which lies bent upon itself 

 in the mantle-cavity. The penis broadens towards the middle and then 

 narrows considerably, to end in a long, slender point. A number of shallow 

 transverse grooves cross the anterior part on one side. 



Unfortunately both the female specimens were slightly immature as 



regards their reproductive organs as well as in their shells. Nevertheless 



the full-grown shell of the male was slightly the smallest of the three 



specimens. This is interesting, as Boycott * has recently shown that in 



* Proc. Mai. Soc, vol. xii, 1917, pp. 127-132. 



