372 PROCEEDINGS OE THE CONCHOLOGlCAL SOCIETy. 



ending in the marginal line of the lip. The outline of the keel 

 curves forward from the back with a uniform expansion some- 

 what in advance of a circular line. The whole lateral surface is 

 crowded with the characteristic undulated ridges with many 

 interpolations of one or two of half length or less, every ridge 

 ending in a spinous tubercle on the keel. 



Specimen No. 2 was exhibited to illustrate the great regu- 

 larity of the characters of the shell. This is a 'dead' shell, a 

 shade less than No. i, but otherwise repeating its features. 



These two are said to have come from the Cape of Good 

 Hope. 



Specimen No. 3 (PI. iii Frontispiece) from an unknown locality 

 is remarkable for an unusual development of the aperture. From 

 a width of one centimetre at the lateral point to that of three 

 centimetres at the keel, the edge of the shell is marked with three 

 strong and many fine lines of growth, the whole forming a sort of 

 final lip upon which the radiating ridges, and particularly the 

 deflected ends of such ridges near the keel, are partially evanes- 

 cent. These final lines of growth follow quite normally the 

 long series seen from within. 



The front edge of the aperture is marked by a distinct pro- 

 longation forwards, deflecting the keel outwards like the lip of a 

 jug, with a regular curve affecting the position of three tubercles. 

 Instead of the expanding curve of the general outline of the 

 keel seen in No. i and No. 2 and all ordinary specimens, this 

 line in this shell is somewhat restricted, so that it appears to be 

 more nearly parallel to the curve of the thickened lip from the 

 axis to the point. This, with the extension of the aperture, 

 gives a somewhat trumpet-shaped figure to the lateral aspect. 



This shell is (except for the pouting lip in front) very much 

 more regular than No. i and No. 2 in the curvature and suc- 

 cession and in the alternations of long and single short ribs, not 

 one of which is wanting or out of place, while all are somewhat 

 more developed and slightly more distant from each other than 

 in No. I. The whole lateral surface is polished in all the speci- 



J.C, v., Oct., 1 888. 



