156 CONTRIBUTIONS 



thick ; spire slightly produced ; suture small, irregular ; 

 whorls five, irregularly canaliculate ; columella much 

 thickened ; canal short ; emarginate ; mouth ovate ; outer 

 lip sharp. 

 Length 1.6, Breadth .1, of an inch. 



Observations. This species in its outline most resembles 

 P. bezoar (Lamarck). In its minor characters it is, how- 

 ever, very different, being smooth. On that part of the 

 whorl which is usually occupied by an angle, the angle 

 is replaced by a slightly impressed furrow, and in most spe- 

 cimens there are indistinct ones above and below this. 

 The seat of the umbilicus is rather impressed, and sur- 

 rounded by an oblique welt terminating at the emargina- 

 tion. The superior part of the columella is very much 

 thickened, and a small channel separates it there from 

 the lip. 



Four species of this genus have been observed in the 

 London Clay of England, and none above or below it. M. 

 Deshayes's Tables give twenty-one. Ten are from the 

 Paris basinseven from Bourdeaux. In the United States 

 three species have been observed in a fossil state. The 

 canaliculata and carica (Lamarck) have been obtained at St 

 Mary's, Maryland. More recently Mr Conrad discovered 

 a new species, sulcosa, described in the Journal of the 

 Academy of Natural Sciences, vol. 6, page 220. 



Great Britain. Appreciating his merits, the Geological Society, having 

 previously awarded him their first Woollaston medal, publicly and appro- 

 priately bestowed it on him, at the meeting of the British Association, at 

 Oxford, in June 1832. 



