MUSEUM OF COMPARATIVE ZOOLOGY. 69 



are crowded together ; the threads, especially the secondary ones, have a rough 

 appearance, perhaps due to the lines of growth ; aperture (excluding the ca- 

 nal) ovate, somewhat abruptly compressed to form the very distinct straight 

 canal ; pillar straight, without callus ; outer lip imperfect in the specimen, 

 but probably thickened in the adult. Lon. of shell, 8.0 ; of last whorl, 4.75 ; 

 of aperture and canal, 3.5. Max. lat. of shell, 3.25 ; of aperture, 1.5 mm. 

 Defl. about 34°. 



Yucatan Strait, 640 fms. 



The specimen is light brown, blotched with a darker shade, but it is doubt- 

 ful if^ this is not accidental to the specimen. The abrupt contraction to form 

 the canal gives it the aspect of a little Fusus. 



P. (Drillia) elusiva n. s. 



Shell small, rather acute, having a dull, ashy, worn appearance, the sculp- 

 ture faint, as if obsolete, although quite perfectly preserved, whorls eight or 

 nine ; nucleus, nuclear whorls, and sculpture of the notch-band precisely as in 

 the last species ; spiral sculpture much the same, excepting that there are 

 from three to six secondaries between the primary threads, and all, both 

 secondaries and primaries, are ill defined and barely elevated above the sur- 

 face ; on the smaller whorls there are eight or ten transverse swellings ex- 

 tending from the edge of the notch-band to the suture, too wide and ill 

 defined to call ribs, and chiefly evident as oblique waves most prominent at 

 the anterior edge of the band ; on the last whorl barely evident as ten or 

 twelve faint nodules just before the band and wholly obsolete before the pe- 

 riphery ; form of the whorls wholly different from that seen in the last species, 

 the whorl and aperture tapering imperceptibly into the short canal, with about 

 seven spiral threads distinguishable as larger than the secondaries ; notch mod- 

 erate ; suture appressed, indistinct ; outer lip thin, simple, moderately pro- 

 duced forward in the middle ; pillar short, twisted, with a thin white glaze on 

 it ; canal distinctly recurved. Lon. of shell, 9.25 ; of last whorl, 5.25 ; of 

 aperture, 4.0. Max. lat. of shell. 3.75 ; of aperture, 1.5 mm.. Defl. about 35°. 



Yucatan Strait, 640 fms. 



A species with no salient characters or attractions, which a sufficiently large 

 series might perhaps show to be an extreme variety of D. pcripla. 



P. (Drillia) morra n. s. 



Shell small, acute, with the Sinusigera nucleus, and seven or eight reticu- 

 lated whorls ; sculpture, on the earlier whorls, of ten or twelve, and, on the 

 last whorl, of twenty-five equal, rounded, close-set riblets, beginning at the an- 

 terior edge of the band, growing stronger and wider to the periphery, after 

 which they again diminish, covering the whorls, and on the last visible nearly 

 to the extreme of the canal ; these are crossed by (on the fourth whorl) four, 

 or (on the last) about twenty- five close-set rounded threads, with a tendency to 

 form a little nodule where they cross the summit of the transverse ribs, and 



