104 THE LAKE EEGIONS OF CENTRAL AFRICA. 



and perhaps boarded by crocodiles, which are hated 

 and dreaded by these black navigators, much as is the 



covering the fissure ; body-whirl flattened, pale olivaceous, with two brown 

 bands, darker at the apex ; lines of growth crossed by numerous oblique, 

 interrupted striae. 



Diameter 5-6, height 3 lines. 



Testa orbicularis, hemisphcerica, late umbilicata (apudjuniores rimata), spira 

 minuta ; apertura magna, valde obliqua ; labio calloso (in testa adulta rimam 

 tegente) ; pallide olivacea, fasciis duabus fuscis zonata ; lineis incrementi 

 striolis interruptis oblique decussatis. 



4. Melania (Melanella) nassa, n. sp. (PI. XLVII. fig. 4.) 



Shell ovate, strong, pale brown, with (sometimes) two dark bands ; spire 

 shorter than the aperture ; whirls flattened, ornamented with six brown spiral 

 ridges crossed with a variable number of white, tuberculated, transverse 

 ribs ; base of body-whirl eight with tuberculated spiral ridges variegated 

 with white and brown ; aperture sinuated in front ; outer lip simple; inner 

 lip callous. 



Length 8|, breadth 5% lines. 



Testa ovata, solida, pallide fusca, zonis 2 nigricantibus aliquando notata ; 

 spira apertura breviore ; anfractibus planulatis, lineis 6 fuscis spiralibus et 

 costis tuberculaiis ornatis ; apertura antice sinuata; labro simplici ; labio 

 calloso. 



P.S. July 27th. — In addition to the foregoing shells, several others were 

 collected by Capt. Speke, when employed, under the command of Capt. 

 Burton, in exploring Central Africa in the years 1856-9 ; these were deposited 

 in the first instance with the Geographical Society, and are now transferred 

 to the British Museum. 



A specimen of Ampullaria (Lanistes) sinistrorsa, Lea, and odd valves of 

 two species of Unio, both smooth and olive-coloured, were picked up in the 

 Ugogo district, an elevated plateau in lat. 6° to 7° S., long. 34° to 35° E. 



A large Achatina, most nearly related to A. glutinosa, Pfr., is the "com- 

 mon snail " of the region between lake Tanganyika and the east coast, 

 Fossil specimens were obtained in the Usagara district, at a place called 

 Marora, 3000 feet above the sea, overlooking the Lufiji River, where it in- 

 tersects the coast range (lat. 7° to 8° S., long. 36° to 36° E.). 



Another common land snail of the same district is the well known " Buli- 

 mus caillaudi, Pfr.," a shell more nearly related to Achatina than Bulimus. 



Captain Speke also found a solitary example of Bulimus ovoideus, Brug., 

 in a musjid on the island of Kiloa (lat. 9° S., long. 39° to 40° E.). This 

 species is identical with B. grandis, Desh., from the island of Nosse Be, 

 Madagascar, and very closely allied to B. liberianus, Lea, from Guinea. 



