PRESTON: HELICOID SHELLS EKOM CAPE COLONY. 17 



Natalina liliacea, n.sp. 

 Shell moderatel}' thin, very depressedly turbinate, yellowish 

 brown above, shading to straw-colour round the umbilical area, 

 somewhat shining; whorls 3^, rapidly increasing, sculptured with 

 closely set, coarse, transverse, arcuate strise which become obsolete on 

 the base of the shell ; base of shell somewhat flattened ; suture 

 impressed; umbilicus rather wide, deep; columella descending 





obliquely, angled below ; labrum pinkish, thickened but scarcely 

 reflexed, projecting in front, receding below, a light but well-defined 

 yellowish callus uniting it with the columella ; aperture irregularly 

 ovate; interior of shell lilac-coloured. Alt. 16'5mm.; diam. niaj. 20, 

 min. 15 mm. Aperture: alt. 9, diam. 10 mm. 

 Hab. — Knysna Forest, Cape Colony. 



ZiNGIS PERLEVIS, U.Sp. 



Shell thin, depressedly suborbicular, pale yellowish flesh-colour, 

 shining; whorls 4, the first three regularly increasing, the last large, 

 quite smooth ; sutures impressed, narrowly margined below ; per- 

 foration extremely narrow, almost concealed by the narrow i-eflexion of 



the columella ; columella reflexed above, descending in a gentle curve ; 

 labrum thin, membranaceous; aperture broadly sub-lunate. Alt. 6-5 mm.; 

 diam. maj. 12, min. 10 mm. Aperture : alt. 6, diam. 6 mm. 

 Hah. — Knysna Forest, Cape Colony. 



Trachtcystis Knysnaensis, n.sp. 

 Shell small, perforate, depressedly turbinate, brownish flesh-colour; 

 whorls 4|-, regularly increasing, the last obtusely carinate at the 



periphery, sculptured with closely set, somewhat wavy, spiral striae, 

 crossed by coarse, arcuate, transverse, membranaceous riblets, 



VOL. X. — MARCH, 1912. 2 



