338 Zoological Society. 



the margin ; anterior slope obscurely radiated ; hinge-line com- 

 pressed in front and tuberculated, wider behind and deeply wrinkled. 

 Length 4f, breadth 2, thickness If inches, 



2. Unio Burtoni. 



Shell small, oval, rather thin, somewhat pointed behind ; umbones 

 small, not eroded ; pale olive, concentrically furrowed, and sculptured 

 more or less with fine divaricating lines ; anterior teeth narrow, not 

 prominent ; posterior teeth laminar ; pedal scar confluent with ante- 

 rior adductor. 



Length 12, breadth 8|^, thickness 5| lines. 



3. LiTHOGLYPHUS ZONATUS. 



Shell orbicular, hemispherical ; spire very small ; aperture large, 

 very oblique ; umbilicus wide and shallow, with an open fissure in 

 the young shell ; lip continuous in front with the umbilical ridge ; 

 columella callous, ultimately covering the fissure ; body-whirl flat- 

 tened, 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. 



4. Melania (Melanella) nassa. 



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

 bands ; spire shorter than the aperture ; whirls flattened, orna- 

 mented with six brown spiral ridges crossed by a variable number 

 of white, tuberculated, transverse ribs ; base of body-whirl with eight 

 tuberculated spiial ridges variegated with white and brown ; aper- 

 ture sinuated in front ; outer lip simple ; inner lip callous. 



Length 8^, breadth 5^ lines. 



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 18o6-9 ; 

 these were deposited in the first instance with the Geographical 

 Society, and are now transferred to the British Museum. 



A specimen of AmpvUaria (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. C° to 

 7° S., long. 34° to 35° E. 



A large Achatina, most nearly related to A. (/luiinosa, Pfr., is the 

 " common snail " of the region between Lake Tanganyika and the 

 East coast. Fossil specimens were obtained in the tJsagara district, 

 at a place called Maroro, 3000 feet above the sea, overlooking the 

 Lufiji River, where it intersects the coast range (lat. 7° to 8° S., 

 long. 3G° to 37° E.). 



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

 " Bulimiis Caillaudi, Pfr.," a shell more nearly related to Achatina 

 than Bulimus. 



Captain Speke also found a solitary example of Bulimus ovoideus, 

 Brug., in a naisjid on the island of Kiloa (lat. 9° S., long. 39*^ to 

 40° E.). This species is identical with B. yrandis, Desh., from the 

 island of Nosse 15(;, Madagascar, and very closely allied to B, lihe- 

 rianus. Lea, from Guinea. 



