KEPORT ON THE GASTEROPODA. 315 



This beautiful little shell, though enclosed in a small glass tube, was found sadly broken, so 

 that the measurement of the breadth of the mouth is somewhat doubtful. It is very like Plcurotoma 

 fragilis, Reeve ; but in that species the spirals are stronger and more remote, and the longitudinals 

 much sharper. Clathurdla magdlanica, Phil., is even liker, but is a much stronger shell, has 

 a shorter mouth, below the suture the upper whorls are contracted and are not so equably 

 rounded ; the apex in that is a little larger, the spirals are more regular, are waved, and are not 

 so much raised, and the longitudinals are much fainter. In Clathurdla swpercostata, E. A. Sm., the 

 upper whorls are ribbed. What it most resembles, however, is the Bda (?) cxpansa of G. 0. Sars, who 

 kindly compared the two species and sent me his unique specimen for examination. That is a 

 much longer and narrower shell, of much faster increase, larger in the apex, and higher and narrower 

 in each corresponding whorl ; the whole spire is thus much more elongated, and the last whorl is 

 very much less tumid ; the shell, too, is thicker, and the whole style of sculpture coarser. In the 

 same length it has about one whorl less. The curve of each of the whorls is more tumid ; and as 

 each slopes down to the straighter suture, it slowly and slightly contracts. 



46. Pleurotoma (Bela) climaJcis, 1 n. sp. (Pi. XXVI. fig. 7). 



Station 106. August 25, 1873. Lat. 1° 47' N., long. 24° 26' W. Mid Atlantic. 

 1850 fathoms. Globigeriua ooze. Bottom temperature 36 - 6°. 



Sliell. — High and narrow, scalar, carinated, finely ribbed, spiralled, with a small body- 

 whorl, contracted rounded base, au insignificant and unemarginated snout, scarcely any canal, 

 and a strongly marked suture. Sculpture: Longitudinals — there are numerous narrow, 

 raised, round-topped, distant, quite straight ribs, more or less tubercled. Of these there 

 are about 20 on the last whorl, and about 15 on that which precedes: one, more or less imper- 

 fect, is occasionally intercalated between the others ; they are crowned round the shoulder 

 of the shell and to some extent elsewhere with small round tubercles ; in the broad hollows 

 between these ribs there are fine Hues of growth. Spirals — immediately below the suture 

 there is a tubercled thread ; on the spire this thread is a strong feature, but towards the 

 mouth it becomes in every way weaker ; below this there is a sloping shoulder, the edge 

 of which is occupied by a flat narrow thread, and forms an angulated keel tipped with 

 small round tubercles ; below the keel the shell becomes nearly cylindrical, with a very 

 slight constriction in a furrow lying between the keel thread and the first of some 17 or 

 18 flat threads parted by narrow flat furrows which occupy the whole of the lower part 

 of the shell ; of these there are about 6 on the penultimate whorl. Each of all these threads 

 in crossing the fine ribs tends to rise into a squarish tubercle. Colour white, under a thin, 

 persistent, glossy, yellowish membranaceous epidermis. Spire high, narrow, conical, scalar. 

 Apex much broken. Whorls : 5 remain ; they are cylindrical, and shortly shouldered 

 above ; the last is small and short, but a very little tumid, with a short rounded base and 

 a small short squarish snout, the point of which is not emarginated. Suture linear, 



1 zXiuax/r, a little ladder, so called from its scalar form. 



