236 



PUNCTURELLA. 



spiral alone which projects ; the entire number of whorls is only. 

 Slit roundish, but acute in front, and drawn out behind (where it is 

 closed by the septum) into a sharp point so as to be lozenge-shaped 

 when viewed in its entire length. Margin straight on the sides, 

 scarce appreciably broader behind than before ; the edge is bevelled 

 off so as to be quite sharp. Inside glassy; feebly marked with the 

 ribs, which as well as the concentric threads, shine through as trans- 

 parent; the opening up into the apex is narrow and deep, but not 

 pointed ; there is no anterior furrow ; the slit as seen from within is 

 roundish, pointed in front, and truncated behind by the short, thin 

 triangular, straight-edged, little oblique septum. 

 Length O12, breadth 0'08, alt. 0*06 inch. ( Wats.) 

 This beautiful species is not improbably full grown, the very 

 small apex seeming to indicate that the species is in its own nature 

 minute. In outline it somewhat resembles P. granulata Seg. ; in 

 sculpture it has relations with P. asturiana Fisch., and P. profundi 

 Jeffr. ; in both respects it may be compared with P. clathrata Jeffr., 

 but is unlike them all, and may be readily recognized by its minute 

 apex. (Wats.) 



Of Culebra Island, West Indies, 390 fms. 



P. sportella WATS. Journ. Linn. Soc. Loud, xvii, p. 37 ; Challenger 

 Gastr., p. 45, t. 4, f. 9. 



P. CIRCULARIS Dall. PL 25, fig. 31. 



Shell white, acutely conical, with the anterior wall slightly, and 

 the posterior wall strongly, concave ; tip sharply recurved, acute, 

 not spiral, directed backward in the middle line ; surface ornamented 

 with about forty very slender radiating lines, fewer toward the 

 apex, with intercalary threads toward the margin ; concentric sculp- 

 ture consisting of extremely delicate, irregularly disposed aggrega- 

 tions of the lines of growth, which now 7 rise above, and now fall 

 below the general plane of the surface, giving it under a strong 

 magnifier a curiously malleated appearance, between the radiating 

 threads, nowhere exhibiting any uniform concentricity ; where the 

 lines of growth cross the radiating threads they form fine overlap- 

 ping scales closely appressed to the threads ; puncture ovate, pointed 

 behind ; margin thickened, perfectly smooth ; septum triangular, 

 inclined forward under the puncture which it almost entirely hides 

 when viewed from below ; basal edge subcircular. Lon. 5*75, lat. 

 5-0, alt. 3-0 mill. (Dall.) 



Florida Strait ; West Indies, 539 fms. 



