64 BULLETIN OF THE 



two sharp raised threads which pass over strong oblique angular transverse 

 projections, are clearly defined in the smaller whorls, but on the later ones 

 become obsolete ; on the last whorl (about six on the middle and nine on the 

 anterior third) in advance of the peripheral nodules are about fifteen sharply 

 raised threads, with interspaces up to 0.5 mm. in width ; other revolving sculp- 

 ture consisting of microscopic striae covering the shell, which in favorable 

 localities in crossing the lines of growth (as, for instance, on the notch-band) oc- 

 casionally give rise to microscopic shagreening, invisible except in a good light 

 and under a good lens ; transverse sculpture consisting only of generally faint 

 lines of growth, and the oblique nodosities above mentioned, which extend on 

 the posterior whorls from the periphery to the suture, and on the last whorl 

 are proportionally smaller ; these vary from eleven to thirteen in number per 

 whorl ; aperture narrow, outer lip much produced forward, columella twisted 

 and tlie canal rather wide and somewhat recurved ; deposit on the body whorl 

 and pillar very slight ; notch wide, reaching nearly or quite to the suture : 

 margins all thin. Lon. of shell, 13.5 ; of last whorl, 7.5 ; of aperture, 5.75. 

 Max. lat. 5.25 mm. Defl. about 38°. 



Station 48, 533 fins. 



It is uncertain whether this should go in Drillia or Plewrotomella in the 

 present perplexing condition of the Pleurotomida and without any characters 

 from the soft parts. The nucleus is, however, precisely the same as in sev- 

 eral species which, so far as external characters go, may be considered typical 

 Lhillias. 



P. (Drillia) gratula n. s. 



Shell slender, acute, white, smooth, but not polished, with ten or eleven 

 whorls when adult ; nuclear whorls as in the last, except that the nucleus itself is 

 smaller and more acute ; notch-hand narrower, occupying only about a quarter 

 of the surface in the smaller whorls, ami descending but slightly, thus giving a 

 somewhat turreted aspect to the spire ; transverse sculpture consisting of eleven 

 to (on the lasl turn) sixteen slightly oblique rounded ribs, faintly evident 

 across the band and anteriorly extending to the suture, or, on the last whorl, 

 well forward on the canal ; these are crossed by (on the smaller whorls) two to 

 four or (on the last one) sixteen rounded threads, distinct in the interspaces 

 and slightly swollen on the tops of the ribs where they cross ; half of those on 

 tin- lasl whorl are in its anterior third, being as usual more crowded on the 

 canal ; the lines of growth are but slightly visible, and there are only faint 

 indications of Bpiral stris ; in addition to this the entire surface is covered 

 with most minute punctations, visible only under a strong magnifier ; notch 

 in the adult very deep, with its edges raised and directed backward, the outer 

 lip produced forward and inward so much as to cover the entire aperture when 

 the shell Lb held SO that the bottom of the notch is kept in view; the outer lip 

 is thickened, and with tour to eight small denticulations rising from it- surface 

 a diort distance within its margin : pillar straight, somewhat thickened : a 



Blight Callus on the body whorl ; canal very slightly recurved ; one adult has 

 Aim n 12, 1881. 



