58 BULLETIN OF TUK 



in two directions ; remainder waxy white, with the peculiar waxy lustre of 

 abyssal shells ; i\mn rather short-fusiform, spire suhlurreted by the concave 

 ante-sutural liaml ; spiral sculpture of about twenty-four flattened threads, with 

 wider interspaces, liefore the band on the last whorl ; only two or three of these 

 thi'eads visible on the upper whorls ; they pass over all the transverse ridges 

 and are a little stronger over thein. Next the suture are small, short, appressed 

 plications, with a tendency to pair, and even to unite above, thus l)ecoming 

 staple-shai)eil ; the ante-sutural band is excav.ated, smooth except for the termi- 

 nations of the plica;, which cease near its posterior border ; near the anterior 

 border the spiral tlireads begin, crossing sharply-projecting short oblique pli- 

 cations (thirteen on the last whorl) which disappear lialf-way from the pe- 

 rii)hery to the anterior end of the canal, and are somewhat angulated just in 

 advance of tlie ante-sutural band ; notch broad and deep ; outer lip thin, pro- 

 jecting ; pillar sliort, thin, twisted ; canal short, broad. Lon. 8.5 ; of last 

 whorl, 5.75 ; of aperture, 4.5. Max. lat. 4.5 mm. 



Yucatan Strait, (j40 Cms. 



There is some variation in form and sculpture of this species ; the above is 

 from a perfect specimen of average characters. I suspect it to be a Bcla ; the 

 form of tiie notch, however, more nearly resembles what is usually understood 

 by MawjiUa. It has no resemblance to any of the Northern f(jrms. 



P. (Mangilia) comatotropis n. s. 



Shell white, porcellanous, eight-whorled ; first three whorls with ten to 

 eighteen distinct deeply llexuous transverse riblets and a narrow longitudinal 

 belt near the suture ; succeeding rather abruptly to this the sculpture of the 

 remaining whorls consists of ((jn the earlier ones) two or three, or (on the last 

 whorl) up to eleven sharp revolving ridges, the one next before the suture 

 being the most prominent ; these are crossed by delicate distinct raised lines 

 following the lines of growth (on the last whorl about twelve to one milli- 

 meter) which are most evident in the interspaces ; suture appressed from 

 above and below, forming a grooved, slightly projecting riblet ; notch not 

 deep, less than semicircular ; aperture rather narrow and short ; pillar smooth, 

 entirely free from callus ; margins simple, not thickened. Lon. of .shell, 6.0 ; 

 of last Avhorl, 3.75 ; of aperture, 2.5. Lat. of last whorl, 2.5 ; of aperture, 1.0 

 mm. Dell, about 27°. 



Cape San Antonio, (540 fms. 



This somewhat recalls the comparatively gigantic Pleurnfoma oxytropis Sby. 

 and Drillia Kennicottii Dall, but is clearly ncjt the young of any descrilied 

 species. 



P. (Mangilia) lissotropis n. s. 



Shell small, slender, somewhat bluntly tipped, with six whorls, shining witli 

 the lustre of parathne ; nucleus rather large, buUate, smooth, translucent, 

 shining ; remaining whorls with transverse, stout, shouldered ribs (on the last 



