MOLLUSCA FROM EQUATORIAL AFRICA. 201 



slightly, obliquely descending, broadly, outwardly expanded, 

 vitreous, both this and the labrum, whicli is also rather brondly, 

 outwardly expanded and narrowly reflexed at the edge, showing 

 the white laminiferous, somewhat irregular growth-periods ; 

 aperture irregularly subquadrate, armed with an erect sickle- 

 shaped parietal lamella, which starts from the up)per margin of 

 the labrum and proceeds downwards in an oblique direction for 

 some distance, when it terminates in a broad, shallow, cup-like 

 projection ; two glassy, lamella^like teeth on the inner margin of 

 the labrum, of which the lower is the larger and is much more 

 quadrate than the upper; a small, interiorly situate, basal denticle ; 

 a minute, sharp, thorn-like denticle at the base of the columella, 

 and a triangular, triiid, projecting denticle or lamella on the 

 upper portion of the columella. 



Alt. 6, diam. maj. 3'25 mm. 



Aperture: alt, 1*5, diam. 1 mm. 



Hah. Urguess, British East Africa (^, Blciyneij Percival). 



Var, ROBUSTA, var. n. 



Shell differing from the type in its larger and more cylindrical 

 form and in the stronger and more fully developed apertural 

 armature, though the system remains the same, 



Alt. 7'75, diam, maj. 3'75 mm. 



Aperture: alt. 1*75, diam. 1*25 mm. 



Hab, Larogi Hills, British East Africa, at an altitude of 6000 

 to 7000 feet {A. Blayney Percival), 



Enuea curvicolumella, sp. n, (PL XXXII. figs. 17, 17 a.) . 



Shell small, perforate, shortly cylindrical, smooth, shining, 

 vitreous, creamy white ; whorls 6, flattish, the first three rather 

 rapidly increasing, the fourth and fifth gradually so, the sixth 

 rather broad in proportion to the remainder ; suture impressed, 

 margined below ; umbilicus modei-ately wide and deep ; colu- 

 mella descending in an angular curve and excavated at the 

 angle, where, on the inner margin, is developed a coarse, lamelli- 

 form protuberance projecting into the interior of the shell ; 

 labrum continuous, somewhat expanded and reflexed, bearing two 

 lamelliform plaits (of which the lower is the larger) on the inner 

 margin of the upper portion, and a coarse, slightly curved, erect, 

 parietal lamella above ; aperture rather elongately subquadrate. 



Alt, 2" 7 5, diam. maj. 1'25 mm. 



Hah. Between the Jombene Hills and JSTyeri, British East 

 Africa {Rohin Kemp). 



Ennba decussatula, sp. n, (PI. XXXIII. figs. 1, \ a.) 



Shell cylindrically ovate, thin, cream-coloured ; whorls 7, the 

 first five regularly increasing, the sixth long in proportion to 

 those above, the seventh also long, but diminishing in breadth 

 and bistrangulate just behind the labrum, sculptured with rather 



Proc. Zool. Soc— 1913, No. XIV. 14 



