424 BASILISSA. 



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

 and a projecting, crenulated, or rope-like thread forming tlie 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 5 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, ap])arently 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 

 laro-ely to cover the umbilicus, it then advances straight and is toothed 

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



Heii^dit '13 in., breadth '14, least "12 ; Penultimate whorl, "03. 

 INIouth, 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.) 



Off Falma, Canaries, 1125 fms. 



B. munda Wats. J. L. Soc. Lond. xiv, p. 596 ; Challenger Rept., 

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



B. suPERBA Watson. PI. 36, figs. 6, 7. 



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

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

 gpii-als — 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 pr()je(;ting 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 

 edo-e 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. 



