Freshwater-Shells from Central Africa. 155 



BuUmus {Cerastus) kidetensis. (PI. V. fig. 9.) 



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

 subpellucido-albida, oblique regulariterconfertim striata et tenuiter 

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

 centes, sutura profunda vix obliqua discreti ; apertura ovata, 

 pyriformis, longit. totius 5 paulo superans ; perist. tenue, mar- 

 gine columellari modice dilatato et reflexo. 



Longit. 15| millim., diam. maj. 8, min. 7| ; apertura 6 longa, 3| 

 lata. 



Hah. Kidete [Emiri) ; on the plains within 50 miles of 

 Mamboia [Last). 



Although similarly sculptured this is a smaller form than 

 B. Lastly 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 umbilicata, ovata, superne producta, parum nitida, 

 albida, epidermide tenui flavescente induta, oblique tenuiter 

 liratula ; anfractus 7, perconvexi, regulariter sublente accres- 

 centes, sutura leviter obliqua, profunda, sejuiioti ; apex obtusus ; 

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

 tenue, margine columellari dilatato, modo loviter reflexo, intus 

 plica obliqua intrante basim versus instructo. 



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

 lata. 



Hah. 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. ptychaxis, 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, caeteri convexiusculi, oblique striati, 

 ultimus circa medium carina obsoleta cinctus ; apertura ovata, 

 longit. totius 5 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. 



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



