422 



BASILISSA. 



angulate at the periphery, nearly flat on the base, with a very slight 

 nick at the point of the pillar, where it joins the inner lip at a 

 slightly obtuse angle. The pillar-lip is straight. It is very little 

 thickened, and is slightly porcelaneous. It advances a little on 

 the edge of the umbilicus ; below this it is hollowed out by a reced- 

 ing curve, but advances again into a slight rounded projection just 

 above its junction with the oater lip. In its whole direction it 

 inclines slightly to the left. Umbilicus oblique-edged, funnel-shaped, 

 being wide in the mouth and deep, with straight converging sides. 

 It is slightly marked with lines of growth and a few faint spirals ; 

 while all the rest of the shell without and within is brightly opales- 

 cent, it is scarcely so at all. 



Alt. -3, diam. '48 inch. ( Watson.) 



The specimen from which this species is described is full grown, 

 and the animal is still within the shell, but the operculum is absent. 



The species has a slight general resemblance to Trochus (Solar -iella) 

 aureonitens A. Ad., but is utterly different, not only in its angula- 

 tion, but in its sculpture. In form it slightly recalls Zonites cellarius, 

 Mull. (Watson.) 



Mid-Pacific, East of Japan, 2050 fms. 



B. lampra WATS., Journ. Linn. Soc. Lond. xiv, p. 593 ; Challenger 

 Gasterop., p. 97, t. 7, f. 5. 



B. SIMPLEX Watson. PL 36, fig. 1. 



Shell a rather narrow flat-based cone, sharply angulated, small, 

 thin, delicate, smooth, glassy, nacreous under a thin white calcareous 

 surface. Sculpture : there are longitudinals, which are faint, hair- 

 like and sinuated, showing the old lines of growth. Of spirals, faint, 

 rounded, and irregular, the whole surface has traces. At the bottom of 

 each whorl is a flat puckered band about O'Ol inch broad, whose 

 upper edge projects sharply, especially on the upper whorls, and 

 whose lower edge is a slight narrow flange, which forms a sharp 

 carina at the periphery. This band forms the upper border of the 

 suture, which is further marginated below by two not continuous 

 rounded threads occupying the top edge of each whorl. The base 

 is covered by about fourteen rounded ridges and furrows, which are 

 rather stronger toward the center, the last one, forming the edge of 

 the umbilicus, being specially so. Color: the surface is a dead 

 slightly creamy white, formed by a thin calcareous layer through 

 which the underlying nacre shines. Spire high and conical. Apex 



