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 aslightly impressed furrow, and in most gpe- 
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 basin—seven 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. 
