The Non-Marine Mollusca of Portuguese East Africa. 173 



approach tlie more specialised type found in Ps. ivalikalensis Pilsbry.* 

 In the remaining teeth the ectocones are distinct, though very small in 

 comparison with the large mesocones, which have rather broad inner flanges. 

 No endocones occur, and the marginal teeth are much more asymmetrical 

 than is usual in the Achatinidae. The transverse rows of teeth are almost 

 straight and have not the slight angle in the centre which occurs in the 

 next species. The radular formulae of the two specimens examined were 

 (25'f H-26)x76, and (25+l + 25)x 73. The radula-sac projects only a 

 very short distance beyond the muscles of the buccal-mass. 



The two salivary glands meet above the oesophagus, which is broad, 

 but does not seem to be dilated sufficiently to forni a distinct crop. It 

 continues back into the stomach, whence arises the intestine, which describes 



' S 10 17 25 



Text-fig. 19. — Pseudoglessiila (Pseudocerastus) boivini (Morel.), 



Kosi Bay, Zululand. 



Representative teeth from the radula ; X 300. 



the usual S-shaped course before finally passing forwards as the rectum 

 (shown on the left of fig. 1, on PL VI). 



Free retractor muscles. — The arrangement of the principal retractor 

 muscles is shown in PI. VI, fig. 4, and is similar to that described in the next 

 species. The powerful buccal retractor, which bifurcates in front, is united 

 posteriorly with the left tentacular retractor ; while the slender penial 

 retractor and the broad retractor of the foot arise in common with the right 

 tentacular retractor. 



Reproductive organs (PL VI, fig. 4). — Owing to the fact that the specimens 

 examined were not quite full-grown it is impossible to give a satisfactory 

 description of the reproductive organs of the present species. They appear, 

 however, to resemble those of Ps. cressyi in having a rather short free 

 oviduct and receptacular duct, a long vagina, and a penis lined by small 

 papillae and bearing a somewhat swollen terminal appendix, to the posterior 

 end of which the penial retractor and vas deferens are attached, the latter 

 apparently passing forwards to the penis embedded in the outer layers of 

 the wall of the appendix. But the penis and vagina are both much more 

 slender than in the next species, and the receptaculum seminis is also 

 unusually narrow, though it is probable that these features are at least 

 partly due to the immaturity of the specimens. 



* Pilsbry : Bull. Amer. Mus. Nat. Hist., vol. xl, 1919, p. 145, fig. 53. 



