REPORT OX THE GASTEROPODA. 99 



of the umbilicus, being specially so. Colour : the surface is a dead slightly creamy white, 

 formed by a thin calcareous layer through which the underlying nacre shines. Spire hi°-h 

 and conical. Apex broken. Whorls 8 (reckoning the first two as broken), of slow and 

 regular increase till the last, which enlarges rapidly ; perfectly flat, with an upper and 

 lower border, sharply angulated and carinated at the periphery, slightly convex but still 

 very flat on the base, with a blunted angulated and carinated umbilical edge. Suture 

 linear, almost invisible, marginated above and below. Mouth perpendicular, rhomboidal, 

 with the body-pillar and basal edges nearly equal, and the pillar and outer lip nearly 

 parallel. Outer lip sharp and thin, not patulous, not descending, advancing at its junction 

 with the body-whorl, then retreating so as to form the broad open sinus, acute-angled at 

 the periphery, slightly arched across the base, nicked close to the point of the pillar. 

 Pillar-lip arched, strengthened by a thin pad ; reverted on the umbdicus so as to leave a 

 slight groove behind it, it has a slight tooth in front. From the body-whorl it bends very 

 much over to the left, so as largely to cover the umbilicus, and then it curves over to the 

 right to join the outer lip on the base at an obtuse angle. Umbilicus small, oblique-edged, 

 funnel-shaped, nearly covered by the pillar-lip, contracted within, scored with hair-like 

 lines of growth. Height 0'255 in. B. - 25, least breadth - 2. Penultimate whorl, 

 0-075. Mouth, heia-ht 0-12, breadth (HI. 



& 



This is a narrower shell than Basilissa alta, Wats., less ornamented and with a smaller umbilicus. 

 Than Basilissa munda, Wats., this is a narrower shell, the flexuous longitudinals are stronger, the 

 supra-sutural bands are stronger, and in that species the infra-sutural band is wanting. 



3. Basilissa munda, Watson (PL VII. fig. 7). 



Basilissa munda, "Watson, Prelim. Report, pt. 3, Journ. Linn. Soc. Lond., vol. xiv. p. 59G. 



Station 85. July 19, 1873. Lat. 28° 42' N., long. 18° 6' W. Off Palma, Canaries. 

 1125 fathoms. Volcanic mud. 



Shell. — Broadly conical, flat on the base, sharply angulated, small, thin, delicate, 

 smootb, glossy, nacreous under a thin white calcareous surface. Sculpture: There are 

 longitudinals, which are very faint but still sharp, sinuated, showing the old lines of 

 growth. Of spirals there are over the whole surface very faint traces. At the bottom of 

 each whorl, about 0"01 inch above the suture, is a sharp narrow thread, which on the last 

 whorl is bordered below by a second, rather higher and sharper, which forms the carina, 

 and which on the spire is buried by the overlap of the succeeding whorl. On the base 

 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. Colour opalescent, from 

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

 surface. Spire high and conical. Apex flattened, with the minute smooth embryonic 



