ON SOUTH AFRICAN ENNEiE. 11 



development of those processes and in the extent to which the 

 peristome is thickened and expanded. 



The divergencies from a conceivable normal type being 

 apparently more a matter of degree in development than a 

 modification of plan, and no series of specimens exactly sup- 

 porting any definite line of departure from such a normal 

 type, it would not seem desirable to attempt to define named 

 varieties, and the species must remain one diflicult to deter- 

 mine. It is hoped that the series of figures chosen to illustrate 

 the species may serve as a guide to the amount of variation to 

 be looked for. 



From these a summarised definition of the species may be 

 drawn up as follows : 



Shell small, elongate-cylindrical, rounded above and below, 

 deeply rimate and narrowly perforate, semi-transparent, 

 polished; whorls about 7, moderately convex and impressed 

 at the suture, sculptured immediately below the suture with 

 transverse rib-strin3 of varying strength, except the first 2| 

 whorls, which are smooth, and the last half-whorl, in which 

 the stria3 are continued across the width of the whorl and 

 around the base ; aperture somewhat roundly trigonal, 

 broader than high, with more or less thickened and ex- 

 panded peristome reflexed on the columellar and basal lips, 

 furnished with at least four processes varying much in 

 development, viz. a moderate, sometimes heavy, in-running 

 parietal plait, a moderate or large, simple or more or less 

 divided labral tooth, a small tooth about the base of the 

 columella, and a wholly internal columellar plait, large or 

 small, more or less thickened below, rounded or produced to 

 a mammillate point at the lower right margin, the colu- 

 mellar lip sometimes bearing a minute subcentral tooth or 

 swelling. 



Height 3'03, width 1"19 mm. (average of 22 specimens 

 measured). 



Hab. — Environs of Grrahamstown, Cape of Good Hope. 



The following are the dimensions of the figured specimens 

 and a few others : 



