PUNCTURELLA. 237 



P. circiilaris DALL, Bull. M. C. Z. ix, p. 75, 1881 ; Blake Gastrop., 

 p. 403, t. 26, f. 7, 7b. 



P. WATSONI Dall. 



Shell small, greenish-white, exactly resembling in sculpture 

 Cranopsis granulata Seguenza (See p. 242, pi. 25, fig. 28); but 

 differing from that species in having the slit of Puncturella in- 

 stead of Cranopsis, and in having a rather higher and narrower and 

 more conical form. The anterior and posterior slopes are not arched 

 to the same extent as in the C. granulata, and the shell is proportion- 

 ately shorter. The nucleus is small and prominent, and the shell as 

 a whole includes two whorls. Max. alt. 3'0 ; max. diam., 2*5 ; max. 

 Ion., 3-8 mill. (Dall.) 



Near Barbados, in 100 fms. ; off Bahia Honda, Cuba, 220 fms. ; 

 of Yucatan, 200 fms. 



P. Watsoni DALL, Blake Gastrop., p. 403. 



P. TRIFOLIUM Dall. PI. 27, figs. 50, 51. 



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, inclined or recurved; surface ornamented with 

 some twenty-four to thirty strongly elevated rounded ribs, smooth 

 for the most part, but undulating a little as they pass over the con- 

 centric 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 num- 

 ber, 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 muscle. Puncture externally circular, as in 

 Qlyphis, internally trefoil-shaped from the projection of the middle 

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



