99 
PsAMMOBiA LIU SORIA. — Shell transversely, oblong-suboval, 
oluish-white, with minute transverse wrinkles ; apex rather nearer 
the anterior end ; anterior margin narrowed, inclining to the left 
at the end and gaping ; cartilage slope rectilinear, with an obtuse, 
obsolete, convex line on the left valve. 
Length three-fifths of an inch. Breadth one inch. Inhabits the 
Southern States. Cabinet of the Academy and Philadelphia Mu- 
seum. 
This shell does not appear to be very common. It seems to 
vary in having often two teeth on each valve, as in Sanguinolaria, 
Donax variabilis. — Shell triangular; anterior margin ob- 
liquely truncated, cordate, suture a little convex ; posterior hinge 
margin nearly rectilinear, suture indented ; base a little prominent, 
beyond a regular curve, near the middle ; valves longitudinally 
striated with numerous, equal, parallel, regular, impressed lines, 
hardly visible to the unassisted eye, and obsolete on the posterior 
margin ; basal edge within crenate. 
Length half an inch. Width nine-tenths of an inch. Thick- 
ness seven-twentieths of an inch. Inhabits the coast of Georgia 
and East Florida. Cabinet of the Academjr and Philadelphia Mu- 
seum. 
Varies very much in color and is a very pretty shell. Its usual 
varieties are red, white, yellow, or elegantly radiated with dilated 
reddish-brown lines, upon a white or yellow ground ; lines are pur- 
purescent within the shell. A very common shell ; I found it 
more particularly numerous on the beach of Cumberland island, 
where, in favorable situations, at the recess of the tide, it may be 
taken up in handfuls, without any intermixture of sand. It is 
very distinct from D. rugosa^ but approaches much nearer to D. 
trunculus, from which it is distinguished by being more abruptly 
truncated before, smaller, and the longitudinal lines are more in- 
dented. I have no doubt but this species has been regarded, by 
authors, as the same with trunculus, if so, judging by an individual 
of that species in the collection of the Academy, at least two dis- 
tinct species have been confounded together under that common 
name. 
Bonax fossor. — Shell subtriangular ; anterior margin short and 
rounded ; posterior hinge slope rectilinear ; base very slightly 
prominent beyond a regular curve at the middle ; valves longitudi- 
