Phileas. 
B. 
Mya. 
Selen. 
Tellina. 
Cardium. 
Mactra. 
Donax. 
Venus. 
Spondylus. 
' Chama. 
Arca. 
Ojirec. 
4Anomta. 
Mytilus, 
Pinna. 
Argonatuta. 
Nautilus. 
Conus. 
Cyprea. 
Bulla. 
Valuta. 
wor M s. 
Shell bivalves with acceffory valves at the 
hinge. | 
Bivalves: [bell with 2 valves. Conchs. 
Hinge with generally a broad thick tooth, 
not let into the oppofite valve. 
Shell open at each end: hinge with a fingle 
or double fubulate reflected tooth, not leg 
into the oppofite valve. 
Hinge with the lateral teeth of one valve not ~ 
let into the other. 
Hinge with remote penetrating lateral teeth. 
Hinge with a complicated triangular middle 
toot^, andan adjoining hollow. 
Hinge with a generally remote lateral tooth, 
not let into the oppolite valve. 
Hinge with generally 3 approximate divari- 
cate tecth. T 
Hinge! with 2 teeth feperated by a {mall 
hollow. 
Hinge in one fhell, with 2 oblique obtufe 
teeth. 
Hinge with numerous penetrating teeth. 
Hinge without teeth; but an ovate hollow. 
. Hinge withont teeth, but generally a linear 
depreffion on the rim, the beak of one 
valve curved over the hinge. 
Hinge without teeth, with a fubulate de- 
preffion, and generally fixed by a filky 
; beard. 
Hinge without teeth: valves united at one 
end and open at the other. 
C. Univalves, with a regular fire. 
Shell with one cell, fpiral involute. 
Shell with many cells, with a hole of com- 
munication. 
Aperture effufe longitudinal, witbout teeth. 
Aperture effufe linear longitudinal, toothed 
each fide. 
Aperture a little contracted and placed ob- 
liquely. 
Aperture effufe; the pillar plaited. 
26. Buccinume 
* 
