179 
DENTALIUM planum. 
TAB. LXXIX.— Fig. 1. 
Spec. Char. Gently tapering and curving, smooth ; 
aperture round; lip a little thickened, sharp 
edged. 
Nearly an inch long, sharp at the smaller end. 
Gregarious, found in moderate quantities in a greenish 
sandy Limestone at Bognor, in masses of considerable size. 
I have a piece about four inches broad, and uniformly filled 
with them as the piece represented, by favour of Mr. Boys, 
.DENTALIUM cylindricumu 
TAB. LXXIX— Fig. 2. 
Spec. Char. Cylindrical or scarcely tapering, nearly 
straight, smooth; aperture round. 
About three-fourths of an inch long, and almost a line in 
diameter ; the smaller end nearly as large as the other. 
The ochraceous sandy Iron-stone stratum near Exmouth^ 
affords these in tolerable plenty, being casts of both the 
outsides and insides of the shells, leaving the empty spaces 
where the shells had been. The casts of the inside look 
