ON NEW TEllRl!:STRlAL AND FLUVIATILE SJIELLS. 183 



12. Diagnoses of new Species of Terrestrial and Fluviatile 

 Shells from liritish and (xerman East Africa, with the 

 Descrijjtion of a now Genus (Eiissoia) hom the Eusso 

 Kyiro River, B.E. Africa. By H. B. Preston, E.Z.S. 



[Received September 27, 1911 : Head November 21, 1911.J 



(Plates XXXI. & XXXII.*) 



The species described in the present paper were all, with (jne 

 exception, collected by Mr. Robin Kemp during his more recent 

 travels in ^British East Africa. As they represent only a very small 

 portion of the large numltei- of species sent home by Mr. Kemp, 

 it will be readilv seen what a vast field there is for investigation 

 in the molluscan fauna of this almost hitherto unknown concho- 

 logical province. 



Ennea microstriata, sp. n. (PI. XXXI. fig. 7.) 



Shell scarcely rimate, ovate, edentulate, moderately thin, cream- 

 coloured ; whorls 6, the first four small, regularly increasnig, the 

 fifbh large in proportion, gibbous, the sixth proportionately 

 longer though not quite so broad, marked especially on the fifth 

 whorl with oblique, distant, regular growth-lines, and sculptured 

 with closely-set, microscopic, scratch-like striae ; suture impressed, 

 closely and rather finely crenellate below ; umbilical area 

 represented by a somewhat broad depression, sloping to an 

 extremely narrow, elongate, and shallow fissure ; columella rather 

 vertically descending in a gentle curve ; la.brum narrowly out- 

 wardly expanded, very slightly retlexed ; aperture sulxpmdrate. 



Alt. 7-5, diam. maj. 5 mm. 



Aperture : alt. 2, diam. 2 mm. 



JIab. Dar-es-Salaam, German East Africa {Connolhj). 



Xatai.ina permembranacea, sp. n. (PI. XXXI. figs. 20, 20 a, 

 20 h.) 



Shell perforate, suborbicular, with almost plannlate spire, 

 membranaceous, pale brownish horn-colour; whorls 5, marked 

 with closely-set, oblique, arcuate, transverse wrinkles; suture 

 impressed, very narrowly margined below ; uml)ilicus moderately 

 narrow, deep ; columella outwardly expanded above, vitreous, 

 descending in an oblique curve, dittused above into a thin, glassy, 

 ill-defined callus which reaches the upper margin of the labrum ; 

 labrum membranaceous,slightlyreflexed, receding below, projecting 

 above ; aperture ovate. 



Alt. 6-25, diam. maj. 14-25, diam. min. 11-75 mm. 



Aperture : alt. 6-25, diam. 7-25 mm. 



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

 {Robin Kemp). 



* For explanation of tbe I'lates see ]>. lO-'i. 



