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 furroweo^ and sculptured 

 more or less with fine divaricating lines ; anteru^Aflh narrow, not 

 prominent; posterior teeth laminar; pedal ^cj^^ffui with ante- 

 rior adductor. 



Length 12, breadth 8, thickness 5^ lines 



3. LlTHOGLYPHUS 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 strise. 



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 spiral ridges variegated with white and brown ; aper- 

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



Length 8y, 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 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 

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

 East coast. Fossil specimens were obtained in the Usagara 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. 36 to 37 E.). 



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

 " Bulimus 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. yrandis, Desh., from the 

 island of Nosse Be', Madagascar, and very closely allied to B. libe- 

 rianus, Lea, from Guinea. 



