48 THE VOYAGE OF H.M.S. CHALLENGER. 



but very minute ; the surface is also delicately fretted with flue concentric undulations, 

 which in crossing the riblets rise into sharp little contiguous tubercles, but iu the narrow 

 intervals are almost invisible. Colour frosted glassy- white. Apex fine, sharp, prominent, 

 projecting upwards and backwards, with only the extreme tip (which is very small) 

 incurled and slightly turned round ; there are fully two whorls. Slit is a largish round 

 hole with a pointed prolongation backwards ; it lies close in front of the tip, and cuts 

 away the natural top of the shell. Margin excessively thin, patulous all round, not 

 crimped. Inside glassy ; a very small hollow runs into the apex ; the lines of the outside 

 ribs are just perceptible ; there is no anterior furrow ; the slit, as seen from within, is 

 round, and is very little interfered with by the short, thin, triangular, straight-edged, 

 little-oblique septum. L. 0*21 in. B. 0-16. H. 0-14. 



It was with very great hesitation I united the Challenger specimens to this species ; and in my 

 paper to the Linnean Society (loc. cit.) I mentioned various points of distinction between the forms. 

 Even there, however, I suggested that a fuller series of specimens than I had seen at the time I 

 wrote might supply connecting links between them. This actually proved to be the case, so enabling 

 me — though only at the very last moment, and after my paper was in print — to suppress the name I 

 had chosen for the species, and to adopt that of the late Dr Gwyn Jeffreys. 



11. Puncturella (Fissurisepta) rostvata (Seguenza) (PI. IV. fig. 10). 



Fissurisepta rostrata, Seguenza, Paleeo. Malac. Terr. Terz. di Messina, p. 10, pi. v. f. 3. 

 Puncturella (Fissurisepta) rostrata, Watson, Journ. Linn. Soc. Lond., vol. xvii. p. 38, sp. 10. 



Station 24. March 25, 1873. Lat. 18° 38' 30" K, long. 65° 5' 30" W. Off 

 Culebra Island, West Indies. 390 fathoms. Pteropod ooze. 



Fossil. — From the Upper Mioceue, Trapani, Sicily. 



Shell. — Very small, thin and high, ovate, with slightly impressed sides, glassy, dotted 

 in regular oblique-curving lines, with high, blunt, minute glassy tubercles ; the side slopes 

 are hio-h and straight, tbe front edge faintly convex, the back slope slightly concave ; there 

 is no embryonic apex ; and the slit is a round hole parallel to the base. Sculpture : The 

 surface of the shell is glassy, but is dotted with minute tubercles which are generally 

 parted by more than their own diameter, and run in very regular oblique sweeps parallel 

 to one another. Colour transparently glassy, the tubercles being dead white. Apex 

 none, the top being slightly bent back and the entire tip removed. Slit : a small round 

 hole on the very top, with slightly irregular sides. Margin very thin ; the sides are 

 almost straight or a little bent in, and the breadth is very slightly greater behind than 

 before. Inside quite glassy ; there is no anterior furrow, and the straight concave-edged 

 septum runs far down the shell parallel and very near to the posterior wall, thus cutting 

 off a long sheath-like process. L. 0*13 in. B. 0*08. H. 0'12. 



