88 
The under side of this fossil, showing the mouth and dentated lip 
of N. conoidea, is represented Plate VI. Fig. 6. 
This, with another specimen, in which the cast is entirely detached 
from the shell, was purchased from the Callonnean collection, and is 
from Courtagnon. 
I have the N. conoidea, in very good preservation, from the Valley 
of Ronca. 
Lamarck particularizes three species of this genus as being found 
among the French fossils : N. conoidea, N. tricarinata, N. mammaria. 
LX. Natica. A nearly globose umbilicated univalve : the opening 
entire and semicircular ; the columella transverse, without teeth, and 
callous externally; the callosity narrowing, or even covering, the 
umbilicus. 
These shells bear considerable resemblance to Neritce, in the form 
of their opening ; but they obviously differ from the shells of that 
genus, in always being umbilicated, and never having their columella 
dentated. 
Natica cepacea, Lam. is a species remarkable for its flattened 
roundish form, and still more for the large thick callous mass, with 
which the umbilicus is covered, in the adult specimens. N. canrena 
is a frequent fossil in the Essex bank of fossil shells. Another species 
of this genus is also frequently found in this bank, which is figui ed 
by Dale, History and Antiquities of Harwich, fyc. Plate X. Fig. 16, and 
by him referred to Cochlea sublivida ore fusco, ad basin cujusque orbis 
velut funiculus depingitur , Lister, Hist. Conchy l. Plate 508, Fig. 19. 
The shell there depicted is evidently N. canrena ; but the Harwich 
fossil shell has a simple umbilicus, and not an umbilicus intersected 
by a callous process, as is the case in N. canrena. This fossil seems 
more nearly to resemble N. glaucina, as represented by Lister, 
Plate 562, Fig. 9, of the same work. 
Among the most rare of the Blackdown fossils, is a Natica, ap- 
proaching in its character to N&eanrena, Linn, and N. epiglottina , 
