1881.] LAKES TANGANYIKA AND NYASSA, ETC. 281 



9. Ennea obesa, Gibbons. 



BuUminus obesa. Gibbons, Taylor's Quarterly Journ. of Conchol. 

 vol. i. p. 255, pi. 2. f. 3. 



Hab. Near Lake Nyassa, and between it and Dar es Salaam 

 (Thomson); "Bawri Island, Zanzibar" (Gibbons). 



This species appears to be a dwarf form of E. ovoidea from the 

 island of Mayotte. The texture is waxy white and semitratisparent ; 

 the peritreme is opaque white ; and the suture is linearly margined. 

 The body- whorl is somewhat flattened just above the aperture, and 

 it ascends chiefly near the lip. The largest specimen from Nyassa 

 is 2S^ millims. long and 13 broad. 



10. Ennea laevigata, Dohrn. (Plate XXXII. fig. 6*.) 



Ennea Icevigata, Dohrn, Proc. Zool. Soc. 1865, p. 232; Pfeiffer, 

 Monog. Helic. vol, v. p. 454. 



Hab. Between Lake Nyassa and the east coast (Thomson) ; on a 

 small rocky island in Lake Nyassa (Kirk). 



Like several other species of Ennea this also varies much in size. 

 Those described by Dohrn were ^^ inch long and | broad, whilst 

 the specimens collected by Mr. Thomson have a length of -^^ inch 

 and a diameter of ^. 



11. BuLiMUs (Rhachis) BRAUNSir, Martens. (Plate XXXII. 



figs. 7-7 c.) 



Bulimus (Rhachis) braunsii, Martens, Von der Decken's Reise in 

 Ost-Afrika, p. 151 ; Nachrichtsblatt der deutsch. malak. Gesell- 

 schaft, vol. i. 1869, p. 150 ; Pfeiffer, Novitat. Conch, vol. iv. pi. 1 18. 

 f. 11, 12. 



Var. hildebrandti, Martens, Monatsberichte Akad. Wissensch. 

 zu Berlin, 1878, p. 294, pi. 2. f. 1, 2. 



Hab. Between Lake Nyassa and the east coast (Ti^owjson); Durum 

 (Hildebrandt) ; Zanzibar (i?ra««s) ; Uzanamo (Capt. Speke). 



The colouring of the specimens which appear to belong to this 

 species is very variable. In one instance it is of a uniform pale 

 straw tint, with the exception that at the apex it is nearly black and in 

 the umbilical region transparent horny. Two other specimens pre- 

 sent markings such as were described originally by Martens, except 

 that the apices are blacker and the two dark zones (one round the 

 middle of the last whorl, and the other below it) are interrupted more 

 or less, and these, together with the series of spots, are nearly black. 

 In another specimen the series of spots flow into one another, thus 

 forming stripes, and those on the lower half of the body-whorl are 

 also confluent ; and again, in another example, the two rows of spots 

 on the upper part of the last whorl are wanting. 



The specimens described by Martens from Zanzibar are said to 

 have had the appearance of young shells, and the last whorl obtusely 

 angulated ; and in the variety hildebrandti it is characterized as 

 very obtusely angulated. In the shells before me, which are larger 

 than those referred to by Martens, the angulation is totally absent. 



Proc. Zool. Soc— 1881, No'. XIX. 19 



