412 MOLLTJSCA OE THE ' CHALLENGER ' EXPEDITION. 



little oblique. Outer lip curves pretty equally from its origin to 

 the edge of the canal, from which to the point of the snout its 

 course is nearly straight : on leaving the body it retires at once, 

 but very slightly and regularly, so as to form the shallow and 

 openly rounded sinus, from which it advances with a long and 

 regular sweep to the front of the mouth, and then curves slowly 

 backward to the point of the snout : it is thin throughout ; above 

 it is straight, but lower down a little patulous. Inner lip spreads 

 rather broadly across the pillar, highly polished, buff-coloured, 

 with a slightly raised edge ; it is very little concave above, 

 straight, but rather short on the pillar, which is cut off to a 

 long fine point, with a blunt, rounded, very slightly twisted 

 strongish edge. H. 1*75. B. 0-68. Penultimate whorl, height 

 0-26. Mouth, height 0-85, breadth 0'45. 



This species has a vague general resemblance to P. sancti- 

 johannis, Sim, from Japan ; but that is not ribbed, and has a much 

 longer mouth. Judging by the figures (see Lischke, Japan M. 

 Conch, pt. 3, p. 22, pi. i. fig. 1, and Weinkauff in Mart. & Chem. 

 Conch. Cab. p. 51, si. 5), it is a good deal like P. Kaderleyi, Lischke, 

 but is smaller, considerably less elongated, and very different in 

 colour. It has a very considerable resemblance to two Eocene 

 Pleurotomas, viz. P. Selysii, Koninck, and P. nodulosa, Lam., 

 between which it occupies somewhat of an intermediate place. 

 Than P. Selysii it is stumpier in the spire, shorter in the pillar, 

 and, especially in the upper whorls, more angulated. Than 

 P. nodulosa it is much larger, each whorl is much higher, the 

 body-whorl is much longer and narrower, and, especially in the 

 young shell, is much more contracted in the base. 



