192 MR. II. B. TRKSTOX OX XEW 



sliglitly outwardly reflexed ; labruin simple, acute ; aperture 

 irregularly roundly ovate. 



Alt. 3-75, diam. maj. 2-75 mm. 



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



Hah. Gazi, British East Africa [Robin Kemp). 



EussoiA, gen. n. 



Shell solid, conical, resembling Assimania, but without oper- 

 culum, though fluviatile in its habits. 



Type of genus, E. inoplna. 



The genus, as above stated, bears a great resemblance to Assi- 

 inania^ but though I have been able to examine a iai-ge number of 

 specimens collected alive, and which still contained the decaying 

 animal, I have been unable to find any trace of operculum : more- 

 over, on physiographical grounds alone, I should be loth to refer 

 it to that genus, which is essentially a coast form, whereas the 

 point at which the present specimens were collected is at least 

 375 miles from the nearest point on the African sea-board, and 

 it is extremely probable, judging by the maps at my disposal, 

 that the connection by water between the locality where the 

 present species was collected and the sea is very much more than 

 that distance ; the Eusso Nyiro after flowing through Lake Lorian, 

 is at present believed to flow out of that lake as the Lakojira 

 Ptiver, a tributary of the Juba, which it joins not far from its 

 mouth and which forms the north-eastern boundary-line between 

 British East Africa and Italian Somaliland. 



Pending the examination of the animal, which in the specimens 

 sent home by Mr, Kemp was not in sufficiently good condition 

 for dissectional purposes, I propose to place the genus tempoiarily 

 in the vicinity of the Assimanieidje. 



EussoiA iNOPixA, sp. n. (PI. XXXII. fig. 10.) 



Shell small, rimate, turbinately conic, dark reddish brown ; 

 Avhorls 5;5, regularly increasing, flattish, except the last, which is 

 somewhat globose, marked only with transverse growth-lines ; 

 suture impressed ; umbilicus very narrow, almost covered by the 

 dilation of the columella ; columella descending in a rounded 

 curve, rather erectly dilated, diffused above into a thin, parietal 

 callus ; labrum simple ; aperture subovate. 



Alt. 3 '5, diam. maj. 2*5, diam. min. 2 mm. 



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



Jlah. Banks of the Eusso Nyiro River, British East Africa 

 {Robin Kern.])). 



^VRMRIVM KIGEZIENSIS, Sp. n. (PI. XXXI. figS. 1, 1 Cl.^ 



Shell very small, triangularly ovate, yellowish red ; both valves 

 closely concentrically striate, the strife being rather coarser 

 towards the umbonal region ; imibones rather lai'ge, not prominent ; 

 dorsal margin sharply arched ; ventral margin gently rounded ; 

 anterior side I'ather abruptly descending ; posterior side sub- 

 I'ostrate, somewhat angularly rounded ; cardinal tooth in right 



