560 ON NEW SHELLS FROM LAKE TANGAN-yiKA. [May 3, 



coloration. Outer lip somewhat expanded, much thickened within, 

 white, concave above, arcuate at the side. Base also thickened and, 

 together with the lower extremity of the whorl, forming a broad, 

 retroverted, and very short cauda. Upper end of labrum joined to 

 the base by a rather thick defined callosity, which spreads over the 

 body-whorl within the mouth. 



Length 35 millim., diam. above the aperture 16; aperture 15 

 long, 9 broad. 



Operculum black, closing the aperture, but at some distance from 

 the peristome. 



Paramelajstia crassigranulata. 



Shell solid (? fossil), imperforate, ovate turreted, dirty whitish 

 (? bleached). Whorls probably about 8 ; four remaining narrowly 

 excavated at the upper part, convexish at the sides, strongly plicate 

 and spirally sulcated and ridged. Plicse arcuate, oblique, 12 to 15 

 on the penultimate whorl, 1 5 to 1 7 on the last, becoming more or 

 less obsolete towards the base. Sulci deep, cutting the plicae into 

 nodules, which number 5 or 6 upon the upper whorls. Transverse 

 ridges on the last further apart below than above the middle, with 

 the exception of 3 or 4 at the extreme base ; these are finer, closer 

 together, and hardly if at all granulous. Aperture, peristome, and 

 basal prolongation very similar to those of the preceding species. 



Length 28 millim., diam. 13; aperture 13 long, 7 wide. 



Fig. 2. 



Paramelania crassigranulata. 



This species, of which we know but two specimens in worn and 

 semifossil condition, is distinguished from the preceding by the nar- 

 rower excavation or tabulation at the upper part of the volutions, 

 and the more rounded and more coarsely granulated ribs and spiral 

 lirse. The general form and the relative proportion of the spire to 

 the length of the last whorl are so much alike in the two forms, that 

 I feel a little hesitation in specifically separating them, bearing in 

 mind the excessive variability of P. nassa. 



