MOLLUSCA OP THE ' CHALLENGER ' EXPEDITION. 249 



same strength as tliis last, and at very nearly equal distances, 

 appear on the base : there are faint indications of others besides, 

 as also of microscopic scratches. Colour like pale flint in thiu 

 flakes ; but the apex is white. Spire high, narrow, conical. 

 Apex consists of 2| embryonic whorls, which form a blunt, 

 smooth, round dome, with the extreme tip immersed but not 

 hid. Wliorls 9-10, pretty high, angnlated, a little constricted 

 and concave above the keel, and very slightly convex below it ; the 

 base is conical, very slightly concave and prolonged into a short, 

 slightly reverted snout. Suture sharp, and slightly canaliculated 

 in consequence of the squarish edge of the inferior whorl not quite 

 reaching the first basal thread ; between these two the suture lies 

 in a minute square-cut depression. Mouth club-shaped, being 

 oval above, with a short, somewhat oblique canal in front. Outer 

 lip well arched, with an extremely slight shallow and open sinus. 

 Inner lip — a very narrow glaze spreads across the slightly concave 

 body, and down the pillar, which is short, rather narrow, and 

 somewhat bent to the left in front ; and here the inner edge is 

 strong, sharp, a little twisted, and runs out to a sharp point at the 

 end of the pillar. H. 0'66. B. 0"23. Penultimate whorl, height 

 0-12. Mouth, height 0'23, breadth O'll. 



The place of this shell is very doubtful ; but there is a very slight 

 upward and backward drawing of the lip below the suture ; and 

 this is further prolonged in a slight concavity, which may be 

 reckoned as a sinus. 



67. Pleueotoma (Deiltja) amblia, n. sp. (a|i/3Xus, blunt.) 

 St. 24. March25. Lat. 18°38'30"N.,long.65°5'30"W. Culebra 

 Island, St. Thomas, Danish W. Indies. 390 fms. Coral-mud. 



Shell.' — High, narrow, conically cylindrical, with a blunt bulbous 

 apex, a contracted base, and an elongated snout, bluntly angu- 

 lated, ribbed, an impressed suture; porcellaneous. Sculpture. 

 Longitudinals — the whorls are crossed from suture to suture by 

 slightly curved, hardly oblique ribs, whose convexity is to the left ; 

 they do not extend to the base of the last whorl ; they are narrow, 

 rounded on the top, feeble above and below, and promiuent in 

 the middle ; tliey are parted by unequal furrows broader than 

 themselves ; there are 17 on the last whorl, and they decrease 

 up the spire, only 12 being found on the first and second regular 

 whorls ; the lines of growth, which agree with the ribs, are fine. 



