716 MR. E. A. SMITH ON SHELLS FROM LAKE NYASSA. [NoV. 6, 



10. Lanistes solidus, sp. nov. (Plate LXXIV. figs. 10, 11.) 

 Shell thick, solid, imperforate when adult, globosely ovate, yel- 

 lowish olive, with the faintest indication of spiral linear bands, 

 smooth with the exception of roughish lines of growth and most 

 minute (almost obsolete) spiral striae not visible to the naked eye ; 

 whorls 4^, with a broad shallow depression or excavation above, then 

 very convex ; last whorl large, ventricose, rapidly enlarging towards 

 the aperture, the latter pyriCormly ovate, purplish, or golden and 

 iridescent within, golden towards the lip and on the columella, which 

 is thickened and reflexed over the umbilical fissure ; operculum 

 horn-colour, concave exteriorly, with the internal scar roughly 

 corrugated. 



Length 42 millims. ; diam. of last whorl, above the aperture, 30. 

 Length of aperture 30, diam. 20. 



Another specimen is 39 millims. long, 28 wide, and its aperture 

 30 in length and 18| in width. 



L. nyassanus of Dohrn is very like the present species in some 

 respects. In solidity, in the absence of an open umbilicus, and in 

 texture it is similar. But the vast difference ot form is of itself quite 

 sufficient to separate the two varieties. Neither can L. solida be the 

 young state of Dohrn's shell, because the specimens before me have 

 all the appearance of being mature, being solid and very heavy for 

 their size ; and on comparison with young examples of that species 

 also obtained by Mr. Simons, the specific distinctness is at once ob- 

 servable. 



11. Lanistes affinis, sp. nov. (Plate LXXIV. fig. 7.) 



Shell ovate, thin, widely umbilicated, greenish olive, with a narrow 

 yellow line winding around the top of the whorls at the suture, 

 smooth, shining, sculptured with oblique lines of increase and most 

 minute spiral striae, which are only visible under a lens ; whorls five, 

 convex ; aperture ovately pyriform, purplish, and iridescent within, 

 becoming yellow at the lips and columella, which is very slightly re- 

 flexed. 



Length 38 millims., diam. 27^. Length of aperture 26, width 

 16|. 



This species may be known from L. solida by its more prolonged 

 spire, which consists of half a whorl more than in that species, and by 

 its open umbilicus, which gives the last whorl a very different form. 



L. ovum, Peters, is another closely allied form, and at first sight 

 might easily be confused with this species. The latter has a shorter 

 and less conical spire, consists of half a whorl less, and its body- 

 whorl and aperture are longer. 



12. Paludina jeffreysi, Frauenfeld. (Plate LXXIV. figs. 

 1,2.) 



Vivipara jeffreysii, Frfld. P. Z. S. 1865, p. 659. 



This species was first found at Lake Nyassa by Dr. Kirk. The 

 specimens collected by Mr. Simons do not quite accord with Frauen- 

 feld's diagnosis. This author has omitted to mention that the en- 



