- 56 - 



Alt. 13.5, diam. maj. 9 75, diam. min. 7.25 mm. 

 Aperture : ait. 8.25, diam, 4.25 mm. 



Hab. — Lake Rekwa^ German East Africa. 



Physa exserta sp. n. — PI. V, fig. 9. 



Shell sinistral ovately fusiform, with exserted spire^ narrowly perforate, 

 thin, semi-transparent, yellowish horn-colour; whorls 4, rather rapidh' 

 increasing, tlie last somewhat convex, marked with coarse, irregular growth 

 lines ; suture very deepty impressed ; umbilicus ver}' naiTOw, deep, almost 

 concealed by the reflexion of tlie columella; columella vitreous, outwardl}' 

 expanded, slightly twisted, descending verticall}'', excavated below, diffused 

 above into a thin, glassy, well defîned callus which reaches the upper 

 margin of tlie labrum; labrum acute ; aperture somewhat irregularl)', 

 inverselv auriform. 



Alt. 15.5, diam. maj. 9.5, diam. min. 8 mm." 



Aperture : ait. 10, diam. min. 5 mm. 



Hab. — Lake Baringo, British East Africa (Robin Kemp). 



Physa laikipiaensis sp. n. — PL V^ fig. 14. 



Shell perforate, ovateh' fusiform with exserted spire, 3'ellowish horn- 

 colour; whorls 4.5, marked only with transverse growth ridges, somewhat 

 convex; suture deeply impressed; umbilicus moderately narrow, deep, 

 parti}' overhung by the reflexion of the columella; columella yellowish, 

 obliquely descending above, ver}' slightly inwardly bulging, curved at the 

 base, outwardly reflexed, the reflexion being gently constricted in the 

 médian part; labrum acute, slightly bent inwards over the aperture above 

 and dilated below; aperture ovate, the rounded pariétal wall bulging 

 into it. 



Alt. 17, diam. maj. 10, diam. min. 9 mm. 



Aperture : ait. 9.25^ diam. 5.75 mm. 



Hab. — Laikipia Plateau, at an altitude of 7,000 feet/ British 

 East Africa (Robin Kemp). 



Physa syngenes sp. n. — PL V, fig. 10. 



Shell allied to P. laikipiaensis, but considerably more elongated and 

 somewhat narrower than that species, the pariétal wall is straight and does 

 not bulge into the aperture and the straight columella descends rather 



