Freshwater- Shells from Central Africa. 151 



Hyalinia Hanningtoni. 



Testa H. Eminianct subsimilis, sed longe minor, magis aperte per- 

 forata, undique minutissirae spiraliter striata ; anfract. 4|, ad 

 suturam marginati, convexiusculi, incrementi lineis tenuibus, 

 aliisque spiralibus microscopicis undique sculpti, ultimus in medio 

 rotundatus ; apertura lunata ; perist. ad marginem columellarem 

 leviter iucrassatum, superne vix reflexum, sed leviter sinuatum. 



Diam. maj. 6| millim., min. 6; alt. 4. 



Hah. Same as IT. Eminiana. 



Although much resembling H. Eminiana^ and at first sight 

 liable to be taken for the young of that species, the present 

 form is quite distinct. The umbilicus is larger, the columella 

 is peculiarly sinuated or notched near its junction with the 

 body- whorl, and scarcely at all reflexed, and the surface is 

 everywhere above and below microscopically spirally striated. 



Hyalinia depressior. 



Testa H. Hanningtoni similis, sed magis eompressa, columella 

 superne breviter expansa et reflexa, apertura latior ; superficies 

 undique distinctius spiraliter striata ; umbilicus angustior. 



Diam. maj. 6| millim., min. 6 ; alt. 4. 



Hah. Mamboia, altitude 4000 to 5000 feet {Last). 



Although the measurements of this form and H. Hanning- 

 toni are similar, still the two species are quite distinct. This 

 can be seen at a glance when they are placed side by side, 

 and the distinctness is confirmed by the differences referred to 

 in the above description. 



Trochonanina mamhoiensis. (PI. V. fig. 3.) 



Testa acute conica, ad peripheriam carinata, tenuissima, anguste 

 perforata, nitida, cornea, pallide fusco-olivacea ; spira elevata, 

 lateribus subrectis vel levissime concavis, ad apicem subobtusa ; 

 anfract. 6-7, mediocriter lente crescentes, supremi 2| eonvexi, 

 minutissime et confertim spiraliter striati, cseteri planiusculi vel 

 vix convexiusculi, infra ad suturam carinati, incrementi lineis 

 obliquis striati, ultimus in medio acute carinatus, inferne leviter 

 convexus, striisque tenuissimis, concentricis, sculptus, baud 

 descendens ; apertura parva, triangularis, longit. totius ^ hand 

 sequans ; peristoma tenuissimum, margine columellari ad inser- 

 tionem breviter reflexo, palUde vinoso, umbilicum semiobtegente. 



Diam. maj. 11 miUim., min. 10 ; longit. 10. 



Hah. Mamboia, 4000 to 5000 feet {Last). 



This is a very fragile shell and well distinguished by its 



