190 MR. II. B. PRESTON ON NEW 



linear, broadly mnrginecl below ; columella, arched, white, 

 extending into a thick, white, narrow, well-defined callus, bearing 

 a single plait above, obliqviely truncate below ; labrum acute, 

 whitish ; aperture narrowly inversely aui'iform. 



Alt. 4"5, diam. maj. 1"25 mm. 



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



Hcth. Gazi, British East Africa {Bohin Kemp). 



Ancylus kempi, sp. n. (PI. XXXI. figs. 2, 2 a.) 



Shell rectangularly ova,te, depressed, somewhat siniious on the 

 left side, with subcentral apex, olive-brown, marked with concentric 

 growth-lines, and indistinctly sculptured towards the margin with 

 faint, ra,diate striee, which are more visible on the interior surface 

 of the shell ; margin acute ; interior of shell polished, shining, 

 pale brown. 



Alt. 1-25, diam. maj. 4'25, diam. min. 3-25 mm. 



Uab. Kigezi, extreme S.W. Uganda, at an altitude of 6000 ft. 

 {Robin Kemp). 



LiMN^A KEMPI, sp. n. (PI. XXXII. fig. 1.) 



Shell small, ovately fusiform, thin, pale reddish brown ; whorls .3, 

 the last large and somewhat elongate, marked with fine, silky, 

 transverse growth-strife ; suture well imj^ressed ; columella 

 obliquely descending, not twisted or arched above, difiused into a 

 very thin, well-defined, parietal callus which reaches the upper 

 margin of the labrum ; labrum simple, acute, somewhat dilated 

 at the base ; aperture very elongately ovate. 



Alt. 7-5, diam. ma.j. 4 mm. 



Aperture: alt. 5, diam. 2-5 mm. 



Hah. Kisumi, Lake Victoria Nyanza,, British East Africa 

 {Robin Kemp). 



Planorbis kigeziensis, sp. n, (PI. XXXII. figs. 5, 5 a, 5 h.) 



Shell small, depressed, suborbicular, with concave spire, thin, 

 pale greenish grey; whorls 4, regularly and rather rapidly 

 increasing, the last obtusely angled above, somewhat sharply- 

 angled below, sculptured with fine, closely-set, arcuate, transverse 

 strife ; suture well impressed ; base of shell not very convex ; 

 umbilical depression very wide, shallow ; columella descending 

 very obliquely and diff"used above into a projecting callus which 

 reaches the upper margin of the labrum ; labrum simple, acute, 

 projecting in front, receding above and below, the mai'gins 

 converging; aperture subelliptical. 



Alt. 1, diam. maj. nearly 3-5, diam. min. 3 mm. 



Hob. Kigezi, extreme S.W. Uganda, at an altitude of 6000 ft. 

 {Robin Kemp). 



Planorbis sperabilis, sp. n. (PL XXXII. figs. 4, 4 a, 4 b.) 

 Shell very small, depressedly orbicular, thin, greyish-yellow 

 horn-colour ; whorls 3, rather rapidly increasing, marked with 



