rium canalicu latum, Lam. Turbo, Brand. Foss. Hunt. Plate X. Fig. 
7 and 8. This shell is distinguished by its being marked, both on 
the upper and under surface, with transverse granulated headings. 
The umbilicus large, funnel-shaped ; crenulated and canaliculated on 
the internal edge of each turn. 
Lamarck describes nine species : A. patulum, S. sulcatum, S. canal- 
iculatum, S. plicatum, S. spiratum, S. ammonites, S. patellatum, 
S. disjunctum, S. bipons. 
XXXVIII. Turbo. A conoidal or slightly turreted shell, the open- 
ing complete, rounded, and not toothed ; the margins always dis- 
joined in the upper part ; the columella smoothed at the base. 
It is from this latter circumstance, the end of the columella smoothly 
blending with the right margin, and not forming a projecting tooth, that 
this genus is separated from Monodonta. Some of the shells of this 
genus very much resemble those of the genus Helix ; but are to be 
distinguished from them by the roundness of their opening not being 
broken, by the projection into it of the last turn but one of the spire, 
which is the case in the helices. Young specimens of cyclostomse 
may also be confounded with turbines ; since, in their young state, 
they also have their margins disjoined, like the turbines ; but, in their 
full-grown state, they become circularly united, which the turbines 
never do. 
Lamarck gives four species of this genus : T. squamulosus, T. ra- 
diosus, T. helicinoides, and T. denticulatus. The latter he has found 
fossil at Grignon. 
XXXIX. Monodonta. An oval or conoidal shell, the opening entire, 
roundish, with the two margins disunited : the truncated base of the 
columella forming a tooth, projecting into the opening. 
This genus, of Lamarck, may be exemplified in Trochus labio, 
Linn. This shell is not among the Paris fossils ; nor do I know of 
its existence among the fossil shells of this island : species of it are, 
however, to be found in the cabinets of collectors. 
