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



noachina. The shell is rather thicker, so that the edge of the aperture appears a little expanded. 

 (' Marginc expanso,' Gould). The sculpture seems about the same in both." The points of distinc- 

 tion here adverted to by Mr Smith are points in which Puncturella noachina presents enormous 

 variations. I have two specimens from the Lofotens, sent by Professor G. 0. Sars, which present 

 these precise features exactly as they appear in Puncturella galeata, Gd. In regard to several other 

 species of Puncturella, I have little doubt they belong to Puncturella noachina, and in particular 

 Puncturella (Cemoria) falklandica, A. Ad. (Sowerby, Thes. Conch., pt. 22, p. 208, sp. 7, pi. x. fig. 14, 

 and Eeeve, Conch. Icon., vol. xix. pi. i. fig. 8), ought to be so classed. Distance between the ribs 

 and equality of breadth before and behind, which are the features referred to for distinguishing the 

 species, are too variable to be relied on for this purpose. Puncturella cooperi, Carp., is a species I do 

 not know, but Dr Carpenter (loc. cit. supra) says of it, " Outside like Puncturella galeata, Gd., but 

 without props to the lamina." This is an entirely variable feature in Puncturella noachina, Linne, 

 and cannot therefore be accepted as a specific distinction. 



6. Puncturella oxia, 1 Watson (PI. IV. fig. 8). 



Puncturella oxia, Watson, Prelim. Report, pt. 16, Journ. Linn. Soc. Lond., vol. xvii. p. 36, sp. 8. 



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

 Islaud, West Indies. 390 fathoms. Pteropod ooze. 



Shell. — Very small, thin, oval, narrowed in front, depressed ; its slopes are straight at 

 the sides, slightly and regularly convex in front ; merely the extreme tip is curled in, and 

 the top projects sharply upwards and backwards immediately in front of the break of the 

 slit ; the surface is closely dotted with minute tubercles ; the slit is rather large and round. 

 Sculpture : There are neither ribs nor concentric lines, but the surface is pretty closely 

 dotted over with minute rough tubercles, which are arranged in somewhat interrupted 

 and irregular zigzags. Colour translucent, and at the tubercles transparent. Apex 

 incurved and turned back, but not bent down ; there are two whorls. Slit : There is a 

 largish round hole obliquely cut off from the top, and prolonged backwards into a point. 

 Margin very thin, patulous, not crimped. Inside glassy ; a very small hollow runs up 

 into the apex ; the surface is scored with many irregular, minute scratch-like white 

 threads, which are more perceptible on a slightly worn than on a fresh specimen ; 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, almost perpendicular septum. 

 L. 014 in. B. 0-1. H. 0"07. 



This species has some features of resemblance to Puncturella profundi, Jeffr., but is flatter, and in 

 sculpture is quite different. 



1 o^iif, sharp. 



