Freshwater- Shells from Central Africa . 167 
the suture, but are most distinct around the umbilical depres- 
sion. 
Ennea peculiaris . (PL VL fig. 18.) 
Testa parva, pupiformis, vix rimata, albida vel pallide straminea, 
nitida, striis confertis, oblique curvatis, conspicuis sculpta; anfract. 
7, apicales duo laevigati, superne obtusi, cseteri convexi, sutura 
leviter obliqua, profundiuscula juncti, ultimus antice contractus, 
pone labrum haud profunde scrobiculatus ; apertura parva, 
longit. totius adsequans, superne peculiariter sinuata, dentibus 
tribus munita ; perist. leviter incrassatum, subreflexum, margini- 
bus callo tenui junctis, dextro superne circulariter sinuato. 
Longit. 4 millim., diam. 2 ; apertura 1 longa et lata. 
Hab . Mamboia, at an elevation of 4000 to 5000 feet {Last ) . 
The peculiar, almost circular sinus at the upper part of the 
aperture is formed by the outer lip bending forward in the 
middle into a tooth-like projection, which is almost met by a 
•prominent but not very thick tooth on the whorl and adjoining 
the termination of the labrum. The third denticle is small 
and situated within the lower margin of the aperture. The 
columella at the upper part seems to exhibit far within a 
broad horizontal plate, but being so far within the aperture, it 
is not easily defined. 
EXPLANATION OF THE PLATES. 
Plate V. 
Figs. 1,1 a. Hyalinia Lasti. 
Fig. 2. FLyalinia Fminiana. 
Fig. 3. Trochonanina mamboiensis. 
Fig. 4. Trochonanina episcopalis. 
Fig. 5. Bulimus (Rhachis) usagaricus. 
Fig. 6. Bulimus (. Rhachis ) quadricingulatus. 
Fig. 7. Bulimus { Cerastus ) mamboiensis. 
Fig. 8. Bulimus ( Cerastus ) Emini. 
Fig. 9. Bulimus ( Cerastus ) kidetensis. 
Fig. 10. Bulimus ( Cerastus P) uniplicatus. 
Fig. 11. Bulimus {Cerastus?) introversus. 
Fig. 12. Bulimus {Hapalus) subvirescens. 
Fig. 13. Bulimus ( Hapalus ) disparilis. 
Fig. 14. Bulimus {Hapalus) associatus. 
Fig. 15. Stenogyra ( Subulina ) subcarinifera . 
Fig. 16. Stenogyra {Subulina,) mamboiensis . 
Fig. 17. Stenogyra {Subulina) usagarica. 
Fig. 18. Stenogyra {Subulina) Lasti. 
Fig. 19. Stenogyra {Subulina) Emini. 
Fig. 20, Stenogyra {Opeas) stenostoma. 
