68 
P. laevigata, P. subcarinata, P. tricarinata, P. elegans, P. clathrata, 
and P. nexilis. 
XXXIII. Fasciolaria. A subfusiform univalve, channeled at its 
base, without any projecting sutures, and having two or three very 
oblique folds on the columella. 
This genus is represented by Murex tulipa, Linn. List. Conch. 
Tab. 910, Fig. 1, et 911, Fig. 2. No fossil shells appear to have 
been found, which can be referred to this genus. 
XXXIV. Pleurotoma. A fusiform, or somewhat turreted uni- 
valve, with the lower part of the opening channeled, and the upper 
part of the lip notched. 
The shells of this genus had been separated from the murices ; 
and, on account of their form, had been disposed by Bruguiere in 
the genus Fusus. But the notch in the lip, resulting, necessarily, 
from a peculiar organization in the animal, fully authorizes their 
arrangement in a distinct genus. This separation of Pleurotoma 
from Fusus, as is justly observed by Lamarck, appears, indeed, to be 
indicated by the considerable number of species which each of these 
genera contains. Of this genus only, he obtained twenty-five species 
from the neighbourhood of Paris : Pl.filosa , P. lineolata , P. clavicularis, 
P. glabrata , P. marginata, P. transversaria, P. catenata, P. dentata, 
P. undata, P. multinoda, P. crenulata , P. bicatenata, P. costellata, P. 
plicata, P. sulcata, P. curvicosta, P. furcata, P. nodulosa, P. ventricosa, 
P. terebralis , P. granulata , P. inflexa, P. turrella , P . striarella , et P. decussata. 
Plate V. Fig. 26, represents a beautiful species of this genus, from 
France. 
