REPORT ON THE GASTEROPODA. 443 



out, but below the middle of the umbilicus it is thickened by a prominent umbilical callus ; 

 below this it is slightly more reverted and thicker than above, and it is very obtusely 

 angulated towards the point of the pillar. Umbilicus, which is defined by the basal 

 carination, is deep ; in consequence of the thinning and hollowing out in the inner lip 

 above and of a strong furrow between the umbilical callus and the basal carina, it looks as 

 if it were large, but it is contracted by the low-lying and strongish spiral callus within. 

 H. 0-67 in. B. 0"6. Penultimate whorl, height 0'16. Mouth, height 0-505, breadth 0'407. 



This species is very like the young of Natica rufa, Born, from Singapore ; but it is higher in the 

 spire ; the umbilical pad, which is white, not brown as in that other, is also smaller, lower in position, 

 and separated distinctly from the pad at the upper angle of the mouth ; the radiating wrinkles on the 

 upper whorls are much stronger and more regular, and the embryonic apex is very much smaller, 

 sharper, and more distinctly defined. Natica vittata, Gm., which in other respects is quite different, 

 has the same pillared umbilicus with carinated edge, a feature, however, not unusual in the genus. 



15. Natica psila, 1 n. sp. (PI. XXVIII. fig. l). 



Station 142. December 18, 1873. Lat. 35° 4' S., long. 18°37'E. Off Cape of Good 

 Hope. 150 fathoms. Green sand. Bottom temperature 47°. 



Shell. — Small, thin, smooth, white, oblique, with a slightly raised spire, a small' apex, 

 an impressed suture, a largish mouth, a thin outer lip, a thickened, rounded, inner lip, and 

 a smallish pervious umbilicus, within which is a broadish but inconspicuous spiral callus. 

 Sculpture: Longitudinals — there are feeble hair-like striae on the lines of growth. Spirals 

 — the whole surface is faintly scored with very minute and quite superficial lines. Colour 

 a waxy white. Epidermis : there are traces of a very thin grey membranous epidermis. 

 Spire short, bluntly conical. Apex small. Whorls 4^, slightly convex, with a slight 

 contraction a little way below the suture. Suture almost horizontal, impressed, sub- 

 channelled. Mouth small, very perpendicular, semicircular ; the upper corner is filled up 

 by a callus. Outer lip thin but blunt ; it retreats a little throughout its whole course ; 

 its curve is very steady, but is a little more flattened above than towards the base. Inner 

 lip very slightly oblique, direct from the insertion of the outer lip to below the umbilicus ; 

 there is a thick callus above in the corner of the mouth and on the body ; it is reverted 

 at the umbilicus, towards the front of which it is slightly excavated ; it is strong and broad 

 throughout. Umbilicus is small but pervious, and very little contracted within, though 

 a broad but inconspicuous callus coils up within it; below this umbilical callus is a 

 shallow furrow. H. 0-37 in. B. 0'38. Penultimate whorl, height 0"1. Mouth, height 

 0-31, breadth 016. 



This species is a good deal like a young Natica sordida, Phil., but is obviously quite distinct. 



1 \JwXoc, rubbed. 



