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Show 1877.] MR. E. A. SMITH ON SHELLS FROM LAKE NYASSA. 715 or elongate, becoming a short line, is situated on the raised infra-sutural thickening, and beneath this two transverse series, sometimes coalescing and forming a short line. On the body-whorl there are other series below the middle, which also in some shells unite and form short flames. 6. MELANIA NYASSANA. (Plate LXXV. figs. 1, 2.) Shell acutely pyramidal, dark madder-brown, thin, somewhat shining ; whorls nine, margined beneath the suture by a distinct raised band, which is marked off by a spiral striation, convex infe-feriorly, and somewhat constricted above ; the few upper whorls with faint longitudinal ribbing, the rest smooth, with a few distant impressed spiral lines, only faintly visible on most of the whorls, but well defined around the base of the last; aperture rather small, madder-brown, oval, acuminate above, occupying about one third the entire length of the shell; columella arcuate, joined to the outer lip by a thin callosity overspreading the body-whorl. Length 14 millims., diam. 4|. Var. Shell narrower, more cylindrical and elongated, the mouth occupying about one fourth of the entire length. Length 20 millims., diam. 5\ (fig. 2). This species is very distinct, on account of its dark madder-brown colour, which is almost uniform, except that the raised band beneath the suture is generally paler brown. The spiral striae are very indistinct on the upper whorls, especially near the middle ; but just below the periphery, and at the base of the ultimate whorl, they become well defined. The variety is represented by a single shell, and in all probability is an abnormal growth ; for in all respects, with the exception of its greater length and more cylindrical form, it is identical. 7. MELANIA NODICINCTA, Dohrn. (Plate LXXV. figs. 11, 12.) Melania nodicincta, Dohrn, P. Z. S. 1865, p. 234. Hab. Lake Nyassa (Dr. Kirk). 8. LANISTES OVUM, Peters. "Lanistes ovum, Peters," Troschel, Wiegmann's Archiv, Jahrg. xi. Bd. i. (1845) p. 215 ; Philippi, in Kuster's Con. Cat. p. 22, pl. 6. f. 2, pl. 7. f. 7 ; Martens, in Pfeiffer's Novitates Conchol. (not seen by me). Hab. Mozambique (Peters), Lake Nyassa (Kirk), teste Dohrn. 9. LANISTES NYASSANUS, Dohrn. (Plate LXXIV. figs. 8, 9.) Lanistes nyassanus, Dohrn, P. Z. S. 1865, p. 233. Two young shells, one about an inch in length, and the other half that size, were the only ones collected by Mr. Simons. Both have the spire completely flattened, and a distinct though rather narrow umbilicus, which, in the adult state, becomes closed by the reflexion of the columellar callosity. |