156 Annals of the South African Museum. 



120^^, and giving to the aperture the drooping appearance of 

 T. (jlohulus ; caUus none. Cohimella erect, with conspicuous 

 wrinkles of growth on the broad upper margin, which is strongly 

 refiexed, almost concealing the deep, narrow perforation. 



Alt. max. 22-8; diam. 19-0; apert. 12-7 x 90 mm.; ends of 

 peristome 6"5 mm. apart. 



Animal unknown. 



Hah. Little Namal.wd. Ookiep (Lightfoot ; Day; Eogers). 

 Buffels Eiver (Eogers). 



Type in coll. Ponsonby. 



The shell selected as Type is the only good specimen I have 

 seen. Its finding-place is uncertain, but bleached shells, exactly 

 agreeing with it in form and substance, have been brought on more 

 than one occasion from the neighbourhood of Ookiep, whence the 

 Type also was probably derived. 



Another white-mouthed race, very similar in form to the above, 

 but of thicker substance, is found further south at Clanwilliam and 

 apparently also at Kangnas and Areb, which may bear, for the 

 present, the same varietal name, although 1 think that when live 

 specimens are discovered they may be found to constitute a 

 distinct species. Intermediates between these unusually elongated 

 races and the typical form of namaquensis also occur and estab- 

 lish a connection between them, which would hardly be apparent 

 if the extremes alone were considered. K peculiarly small example 

 from Clanwilliam is shown on Plate II., tig. 9. 



Trigonephkus lucanus (Miiller). 

 (PI. II, f. 10. PI. IV, f. 4, 13, 21, 29. PL V, f. 5, 10.) 

 1774 Helix lucana, MiilL, Verm. ii. p. 75. D. 



Shell rather large, subglobose, deeply umbilicate, rather thin, 

 translucent, chestnut-brown, paler underneath, with a narrow infra- 

 sutural white line ; peristome white ; interior pale brown. Spire 

 moderately elevated, apex blunt. Whorls 5, rounded, rapidly in- 

 creasing, all except the first H covered with very close, faint, regular 

 transverse striae, extending more faintly into the umbilicus, and 

 faint malleation, more pronounced towards the aperture. Suture 

 rather shallow and crenulate. Aperture truncate-ovate ; peristome 

 slightly thickened and reflexed, ends joined by a faint callus. 

 Umbilicus narrow but deep, extending to the apex. 



Dimensions of a typical specimen from Cape Point, which agrees 



