292 MR. E. A. SMITH ON SHELLS FROM [Feb. 15, 



but dififerences of coloration and sculpture. M. tanganyicensis 

 has the upper part of the whorls of the spire somewhat swollen and 

 almost blacli, the lower half being light chestnut, the black portion 

 beneath this in each whorl being concealed by the upper part of the 

 succeeding volution. 



34. Melania(Melanella)nassa, Woodward. (Plate XXXIV. 

 figs. 26-26 b.) 



Melania (Melanella) nassa, "Woodward, P. Z. S. 1859, p. 349, pi. 

 47, f. 1 ; Smith, P.Z.S. 1880. p. 348 ; Reeve, Con. Icon. fig. 216; 

 Brot, Con.-Cab. pi. 6. f. 7. 



This Tanganyikan shell is subject to much variation, both in form 

 and sculpture. * The number of plicae in two of the specimens collected 

 by Mr. Thomson is exceptionally small, there being but ten upon the 

 last whorl. In contrast to this another example has twenty-six upon 

 the same volution. One of the two former is also abnormal in 

 another respect, namely in having the transverse ridges very narrow, 

 thread-like, continuous on and between the plications, and of a brown 

 colour. In the other they are whitish, interrupted by brown dots 

 upon the lower part of the last whorl. The solid marine character 

 of this species distinguishes it from all others, and when the oper- 

 culum, at present unknown, and the animal are examined, it will 

 probably receive distinct generic rank. 



Since writing the above, another series of this remarkable species 

 has been sent to the Museum by Dr. Kirk of Zanzibar. Among this 

 set are some exceptionally large specimens, peculiar also for a sub- 

 truncation near the base of the columella. This I imagine would be 

 concealed when the shell arrived at maturity by a deposition of 

 calhis. Although of very large size, not one of these appears to 

 be adult, judging from the thickness of the outer lip. The number 

 of transverse lirse on the last whorl is unusually large ; and the 

 whorls are broadly and flatly gradated. 



35. Melania ( ?) horei. (Plate XXXIV. fig. 27.) 



Melania ( ?) horei, Smith, Annals & Mag. Nat. Hist. ser. 5, 



vol. vi. p. 427 (1880). 



Shell ovate-conical, smooth, brown, with a narrow white line 

 beneath the suture. Spire conical, a trifle excentric, inclining very 

 slightly to the right (the aperture being towards the eye and down- 

 wards). Whorls 6|, scarcely convex, exhibiting faint incremental 

 striae. Suture simple ; last whorl rising somewhat upon the pre- 

 ceding near the aperture, then suddenly descending to the margin of 

 the labrum, furnished with a slight basal thickening, aperture ovate, 

 rather acuminate above, purplish brown, occupying about f of the 

 entire length. Lip a little thickened, especially towards the suture, 

 and somewhat patulate near the base. Columella whitish, mode- 

 rately arcuate, united to the upper extremity of the labrum by a 

 thin callosity. Length 14 millims., diara. 6| ; aperture 6 long, 4 

 broad. 



Hab. Lake Tanganyika (Hore). 



