A. ii v M.INA Watson. PI. .'1'J, tiir. "><>. 



Shell oval, suhiribhons, ;i little aliruptly contracted and .slightly 

 constricted and truncated above, striatrd. thin, hyaline, uinhilicated, 

 with a loutish curved mouth. Sculpture: Longitudinal;- there 

 art- very many slight equal hair-like lines of growth. Spirals 

 with the exception of a narrow, nearly medial hand which is smooth, 

 the whole surface is scratched with fine, smooth, regular, sqnan--< -ut, 

 widely parted furrows. These are rather more regularly arranged 

 above than below, where the interstices are more wide and le-s reg- 

 ular ; but toward the end of the shell in both directions the fur 

 tend to become crowded ; they extend to the very edge of the fun- 

 nel-shaped depression of the apex ; but the depression itself is 

 smooth, except for the twisted edge of the outer lip, which at the 

 generic sinus is reverted as usual, but somewhat narrowly ; in front 

 they score the umbilicus on one side, but do not quite extend to the 

 edge of the pillar. Colour hyaline to translucent. Mouth long, 

 curved, rather narrow, and not much enlarged in front. Outer lip 

 convex, posteriorly produced ; the generic twisted sinus is rather 

 small, above it the lip rises and advances, and forms a sharp curve, 

 from this point the lip runs out to the right, at first straight or 

 faintly concave, and here a little contracted, but afterwards with a 

 very regular curve, and increasingly patulous to the point of the 

 shell. Top very obliquely truncate, with a bluntish edge and a 

 small funnel-shaped depression, which, through- the generic sinus 

 leads into the interior of the shell. Inner lip : there is no glaze on 

 the body, the curve of which is a little gibbous above; the pillar 

 edge is narrow, reverted, bluntly toothed, twisted and truncated in 

 front ; at the top of the pillar this edge is very much t\vi>t-,l, and 

 is there separated from the body, leaving a very narrow but deep 

 fissure communicating with the deep umbilicus which lies behind, 

 and is partly covered by the expanded and projecting pillar 

 Alt. 0-44 in. diam. <>"J4. Breadth of mouth at same place, 0'07 

 inch ( H */.--. . 



Levnht. /'///, li? fms. ; Wednesday Itlaadandnt 

 Awftrn/iu. ',-,s fms. 



Ahj.< hynlimt WATS., Chall. Gastr. p. Ii4<>, pi. 4>\ f. 1. 



I do not know any Atji-" with which to compare this very beauti- 

 ful and delicate species. It has something of the gibbosity of 

 eyKtldrioa (Helb. ), var. .W/fA/, in its stumpiest forms ; but the t- \- 

 ture of the shell, the sculpture, and the umbilicus, are very differ- 



