REPORT ON THE GASTEROPODA. 301 



The base of the shell is somewhat swollen, and prolonged into the shortish, broad, and 

 •very unequal-sided snout, which lies quite on one side of the base. Suture strong and 

 slightly canaliculated. Mouth large, almost rhomboidally pear-shaped, sharply angled 

 above, and with a broad open canal below. Outer lip, very regularly curved through- 

 out ; its edge, which is thin and sharp, retreats at once on leaving the body, forming 

 an open V-shaped sinus, which is rounded at the angle ; below this it sweeps down- 

 wards and very little forwards, forming a very low-shouldered wing ; towards the 

 lower part of the mouth it curves very regularly backwards to the point of the pillar. 

 Inner Up, which is polished and porcellanous, is rather broadly excavated in the substance 

 of the shell ; it is scarcely convex on the body, very slightly concave at the junction with 

 the pillar, which is narrow and short, being very obliquely truncate in front, with a fine, 

 but strong, sharpish twisted edge. H. 1'26 in. B. 0"52. Penultimate whorl, height 0'23. 

 Mouth, height 0*6, breadth 0-34. 



I have marked the specimen from Station 1G9 with a query. It is very much rubbed ; but the 

 sculpture of the shell, and even of the sinus scars, is perfectly preserved. This and the proportion 

 and form of the successive whorls are similar, though the line of keel lies a little higher ; the shoulder 

 is squarer and shorter, while the line from the keel to the suture is longer. Were the localities of 

 the two less distant and dissimilar, I would not hesitate. Still the depth at which they live may 

 secure similar conditions for the species even from 35° N. to 37° S. ; and in any case I do not feel 

 able to part the specimens. 



In its expressed keel this very remarkable shell recalls the young of Plcurotoma tornata, Dillw.j 

 or of Plcurotoma circinata, Dall. In form it is slightly like Plcurotoma spirata, Lam., or Plcurotoma 

 obcsa, Reeve. The resemblance most striking of all, however, both in form and sculpture, is one to 

 which my attention was kindly drawn by Dr H. Woodward — that, viz., to Plcurotoma cataphracta, 

 Brocchi, a fossil from the Upper Miocene of the Vienna basin and Northern Italy (Brocchi, vol. ii. 

 p. 221, No. 52, vol. viii. p. 16 ; Lam., Anim. s. vert., vol. ix. p. 367 ; and Philippi, Enum. Moll. Sicil., 

 vol. i. p. 199, vol. ii. p. 171). Compared with that species, this New Zealand form is slimmer, the 

 angulation of the whorls is less, but the keel on the angulation is more prominent though less nodulous 

 and much lower placed, and the sinus is more remote from the suture and is sharper. 



This and the following species are classed under Gcnota, in accordance with what is seemingly 

 the principle indicated by the arrangement adopted in the British Museum, though I doubt whether 

 that accords with Adams' idea of their genus. Cryptoconus might perhaps offer a better place for 

 them, but I do not know the shells of that group well enough, not understanding its diagnosis 

 sufficiently, to judge. 



29. Pleurotoma (Genota) atractoides, 1 Watson (PL XX. fig. 8). 



Plcurotoma (Genota) atractoides, Watson, Prelim. Report, pt. 8, Journ. Linn. Soc. Lond., voL xv. 



p. 407. 



Station 210. January 25, 1875. Lat. 9° 26' N., long. 123° 45' E. Philippines. 

 375 fathoms. Blue mud. Bottom temperature 54 - l°. 



1 arguxrotidr);, spindle-shaped. 



