EEPOET ON THE GASTEEOPODA. 563 



on the upper part of the spire ; round the base of each whorl is a suffused pale tint of 

 brown, which is more or less the colour of the base of the shell ; the point of the pillar is 

 white. Spire high, narrow, and conical, slightly slewed to the left ; so that while the 

 left slope is straight, almost concave, the right slope is just perceptibly convex. Wliorls 

 probably 22, but of these the three or four apical ones are broken off; they are of very 

 slow increase, flat, constricted on their upper part, flatly prominent in the middle, and con- 

 tracted at the lower part ; the base of the shell is flatly conical. Suture strongly defined 

 by the depression in which it lies, but itself linear and projecting, being minutely 

 marginated both above and below. Mouth squarely oval, pointed above, and at the front 

 of the pillar by the canal, which is small. Outer lip broken. Pillar short, small, straight, 

 scarcely excavated or twisted, at the point sharp and slightly advancing outwards. Inner 

 lip : a very thin layer of glaze is carried across the body, and turns round the pillar in a 

 few microscopic lines, by which alone it can be traced. H. 0"6 in. B. - 12. Penultimate 

 whorl, height 0-072. Mouth, height 0D8, breadth 0-06. 



This lias a good deal the proportions of Bittium (Lovenclla) metula (Lovijn), with a narrower base. 

 It slightly resembles the Triforis pfeifferi, Crosse, and (apparently, for the British Museum tablet has 

 more than one species on it) the Iriforis scitula, A. Adams, both from South Australia ; but these have 

 only one series of gemmules, the upper row being very much smaller, and in both the whole shell is 

 very much smaller and slenderer. Triforis gigas, Hinds, is a much thinner and less strongly tuber- 

 cled and sutured shell. Triforis angustissima, Desh. (Moll, de Bourbon), is larger, broader in proportion, 

 has the lower (in his description " superieure," as he reverses the shell) row of tubercles larger, and 

 lacks the infrasutural flat constriction with its small and finely tubercled spiral. Triforis aspcra, 

 Jeffr., is a smaller shell, with outlines more straight, smaller tubercles, a less impressed suture, and a 

 more conical base. 



4. Triforis hebes, Watson (PI. XLIII. fig. 7). 



Cerithium {Triforis) hebes, Watson, Prelim. Eeport, pt. 5, Journ. Linn. Soc. Lond., vol. xv. p. 103, 



sp. 3. 



Station 135c. October 17, 1873. Lat, 37° 25' 30" S., long. 12° 28' 30" W. Nightin- 

 gale Island, Tristan da Cunha Islands, South Atlantic. 100 to 150 fathoms. Rock, shells. 



Shell. — Cylindrically conical, blunt, uncontracted towards the base, strong, translucent, 

 hardly glossy. Sculpture : Longitudinals — on the last whorl there are about 20 longitu- 

 dinal rows of rounded tubercles, parted by depressions of much the same breadth and 

 form as themselves ; they run more or less continuously and straight up the spire from 

 whorl to whorl. There are indistinct lines of growth. Spirals — on each whorl the 

 tubercles are arranged in three spiral rows, parted by rather deep but narrow squarish 

 furrows. The highest row is rather smaller and less prominent than the others. The 

 base of each whorl is sharply but not deeply constricted ; the edge of this constriction 

 appears on the margin of the base as a rounded thread, defined by a slight furrow, which, 



