76 BULLETIN OF THE 



Station 44, 539 fms. 



This species differs in various details from Puncturella profundi Jeffreys, and 

 is apparently nearer his P. granulosa from the Norwegian coast and the Porcu- 

 pine Expedition (60 - 292 fathoms). That species has no concentric sculpture, 

 however, and has not been fully described as far as is known to me. It be- 

 longs, with the preceding and with Puncturella Cooperi Carpenter, from the 

 northwest coast of America, in the genus Fissurisepta of Seguenza. This dif- 

 fers in most specimens by having no props to the septum, a character, however, 

 which is not constant even in the same species, as in a large series of Alaskan 

 forms I have found every transition from fully developed props to none at all, 

 in specimens which differed in no other character. Hence, while it may be a 

 permanent feature in some species, I doubt if it is yet sufficiently established 

 to be safely used as a generic character. 



Puncturella trifolium n. s. 



Shell brownish white, acutely conical, -with anterior and posterior walls 

 nearly straight, except near the tip where they are- slightly concave, especially 

 the latter ; tip erect, squarely truncated at the top, not twisted, incb'ned, or 

 recurved ; surface ornamented with some twenty-four to thirty strongly ele- 

 vated rounded ribs, smooth for the most part, but undulating a little as they 

 pass over the concentric sculpture and rarely and irregularly spinous ; these 

 spines do not exceed two or three on any rib, occur only on the stronger ribs 

 and are short, pointed, solid, and acutely triangular ; between the primary 

 radiating ribs are secondary ones about equal in number, but not spinous, and 

 not raised above the concentric sculpture ; the latter is not strictly concentric 

 except in a general sense, and consists of stout spongy bands connecting the 

 ribs, passing from base to base between each pair of primary ribs on a level 

 with the secondaries, but not evenly continuous clear around the shell, and 

 having a pumice-like texture, so that the bands are not defined sharply like the 

 ribs ; the spaces left vacant by this reticulation are rather deep, and have a 

 worm-eaten appearance ; shell inside smooth, with shallow grooves indicating 

 the stronger external ribs and with a striated space over the head between the 

 anterior horns of the scar of the great pedal muscles. Puncture externally 

 circular, as in Glyphis, internally trefoil-shaped from the projection of the mid- 

 dle of the septum and two little shelly knobs on each side into the spare ; 

 septum triangular, very small and short, inclined in about the same plane as the 

 anterior wall of the shell, in the middle of its lower edge produced and thick- 

 ened like a little short tongue ; about half-way between the base of the septum 

 and the outer upper surface of the perforation inside the tube and at about 

 equal distances from each other and from the median line of the septum, atv 

 two little shelly triangular projections, which give to the interior of the apex, 

 when looked through, tin- trilobate outline referred to in the specific name; 

 base of the shell ovate, the margin showing projections and indentations corre- 

 sponding to the sculpture of the exterior. Lon. 14.0 ; lat. 10.5 ; alt. 7.0 nun. 



