165 
CHAMA digitata. 
TAB. CLXXIV. 
Spec. Char. Palmate,, slightly recurved, gibbose, 
with five or six marginal elongated canalicu- 
lated processes ; surface smooth* 
This is an oblique elongated curved shell, with several 
ridges upon the deeper valve, that are drawn out at the 
margin into hngerrlike processes, which are concave be- 
neath, and some of them slightly expanded towards 
their ends. The attached valve is unknown. 
We are to thank the zeal of our friend, the Rev. Mr. 
Buckland, tor communicating this curious species : casts 
of it very neatly formed, are contained in masses of po- 
rous flinty Chert ; the space formerly occupied is some- 
times partially filled with brown Oxide of Iron or 
Cafcedony. The casts of the inside are often hollow, and 
lined with quartz crystals. 
The texture of the stone, and partial union of the two 
sides of the casts to each other, have rendered it impos- 
sible to expose the whole outline of the shell. I have 
given figures of four specimens that illustrate each other ; 
the two upper ones exhibit the claws (if I may so call the 
marginal processes) ; one of them (fig 1.) is a cast of the 
external surface : the other (fig. 2.) (which has been acci- 
dentally reversed by the engraver) shews a greater 
elongation of the processes, and a hollow with quartz 
crystals ; the lower figures are from two varieties, a 
broad shallow one and a narrow very deep one ;* the 
claws of these have been completely entangled in the 
* Such varieties often occur in shells of this Genus, as well as among 
oysters. 
