OCR Text |
Show 1881.] LAKES TANGANYIKA AND NYASSA, ETC. 281 9. ENNEA OBESA, Gibbons. Buliminus 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 semitransparent; 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 28|- millims. long and 13 broad. 10. ENNEA LAEVIGATA, Dohrn. (Plate XXXII. fig. 6*.) Ennea la?vigata, 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 fy inch long and J broad, whilst the specimens collected by Mr. Thomson have a length of ^ inch and a diameter of -f^. 11. BULIMUS (RHACHIS) BRAUNSII, 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. 118. 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 (Thomson); Durum (Hildebrandt); Zanzibar (Brauns) ; Uzanamo (Gapt. 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 present 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 |