Freshwater-Shells from Central Africa. 155 



BuUmus {Cerasttts) hidetensis. (PI. V. fig. 9.) 



Testa angustc umbilioata, elongato-ovata, superne prolongata, nitida, 

 subpellucido-albida, oblique regularitcrconfertim striata et tenuiter 

 lirata ; apex mediocriter acutus ; anfract. 8, convexi, lente cres- 

 ceutes, sutura profunda vix obliqua discreti ; apertura ovata, 

 pyriformis, longit. totius | paulo sui)erans ; perist. tenue, mar- 

 gine coluraellari modice dilatato et retlexo. 



Longit. loj millira., diam. maj, 8, min. 74 : apertura G longa, 3| 

 lata. 



Hob. Kidete {Emin) ; on the plains within 50 miles of 

 Mamboia {Last). 



Althougli similarly sculptured this is a smaller form than 

 B. Lasti, the spire is longer, and the proportions altogether 

 different. A small variety, consisting of seven whorls and 

 only 12 millim. long, was collected by Bishop Hannington in 

 Usagara. 



BuUmus [Cerastus?) uniplicatus. (PI. V. fig. 10.) 



Testa anguste umbilioata, ovata, superne producta, parum nitida, 

 albida, epidermide tenui fiavescente induta, oblique tenuiter 

 liratula ; anfractus 7, perconvexi, regulariter sublente accres- 

 centes, sutura leviter obli(iua, profunda, sejur.cti ; apex obtusus ; 

 apertura parva, ovata, longit. totius ^ paulo superans ; perist. 

 tenue, margiue columellari dilatato, modo leviter reflexo, intus 

 plica obli([ua intraute basim versus instructo. 



Longit. 14 millim., diam. maj. 7^, min. 6| ; apertura 5^ longa, 3^ 

 lata. 



Hab. Mamboia, at an elevation of 4000 to 5000 feet. 



This species has a fold towards the base of the columella 

 similar to that in B. pti/chaxis, Smith, a much larger shell 

 from Ujiji. The peristome on the columellar side is not 

 much re flexed over the umbilicus, but forms a continuous 

 curve with the basal margin. 



BuUmus {Cerastus?) intrnversus. (PI. V. fig. 11.) 



Testa elongata, superne acuminata, anguste rimata, baud nitida, 

 tenuis, viridi-cornea ; apex introversus ; anfract. 7, duo vel tres 

 primi subfortiter costulati, ca^teri convexiusculi, oblique striati, 

 ultimus circa medium carina obsoleta cinctus; apertura ovata, 

 longit. totius \ paulo superans ; perist. tenue, margine colu- 

 mellari sublate dilatato, supra rim am aliquanto reflexo, intus, 

 basim versus, oblique subtruncato vel plicato. 



Longit. 16 millim., diam. 7; apertura 6 longa, 4 lata. 



Hab. Mamboia, at an elevation of 4000 to 5000 feet. 



