424 BASILISSA. 



there are about eleven fine spirals, within which is a strong furrow, 

 and a projecting, crenulated, or rope-like thread forming the edge 

 of the umbilicus. Color opalescent, from the under-lying nacre 

 shining through the polished, thin, translucent calcareous layer of the 

 surface. Spire high and conical. Apex flattened, with a minute 

 smooth embryonic 1 whorl slightly projecting. Whorls 6, of regular 

 and slow increase (but the specimen is not full grown) ; in profile 

 perfectly flat, the slope being scarcely broken by the supra-sutural 

 thread. Suture linear, almost invisible. Mouth perpendicular, 

 irregularly rectangular, broader than high. Outer lip sharp and 

 thin, with a slight open sinus, sharply angled at the periphery, 

 slightly arched across the base, apparently nicked at the point of the 

 pillar. Pillar-lip arched, strengthened by a thin pad, reverted on 

 the umbilicus so as to leave a groove behind, with a slight tooth in 

 front. From the body it bends very much over to the left, so as 

 largely to cover the umbilicus, it then advances straight and is toothed 

 in front. Umbilicus small oblique-edged, with a crenulated margin. 



Height vl3 in., breadth '14, least '12; Penultimate whorl, '03. 

 Mouth, height *06, breadth '05 inch. ( Watson.) 



Than Basilissa simplex Wats., this is a broader, smoother, less 

 banded shell. Than Basilissa alta Wats., it is lower, less ornamented, 

 with a much smaller umbilicus. ( Wats.) 



OfPalma, Canaries, 1125 fms. 



B. munda WATS. J. L. Soc. Lond. xiv, p. 596 ; Challenger Kept., 

 p. 99, t. 7, f. 7. 



B. SUPERBA Watson. PL 36, figs. 6, 7. 



Shell high, concavely conical, flat-based, sharply angulated, thin, 

 finely reticulated, cream-colored. Nacre very faint. Sculpture: 

 spirals there are about twenty delicate threads, very nearly but 

 not quite regular in thickness or distance, on the upper part of the 

 last whorl ; they slowly decrease in number on the previous whorls. 

 The two (or three) which form the carina are thrown out a little on 

 a projecting whitish fillet, which encircles the base of the whorls. 

 This whitish fillet extends to the base, when it forms a narrow 

 obliquely-corrugated edging. On the base there are about thirty 

 spirals, more crowded, flattened, and irregular than above, and the 

 edge of the umbilicus is defined by another whitish fillet, orna- 

 mented with about thirty oblong beads. One or two smaller and 

 more faintly beaded threads lie within the edge of the umbilicus. 



