122 CLASS ACEPHALA. 
itself in the sand, which it excavates with considerable 
rapidity on the approach of danger. 
Several species are found along the coast of France. 
We might distinguish those species in which the teeth ap- 
proximate in the middle: some of them have still a long and 
narrow shell. (Solen legumen, Chemn. VI. v. 32—34.) 
In others it is wider and shorter; their foot is extremely 
thick. ‘Two of the latter inhabit the Mediterranean. ° (Solen 
strigilatus, &c.) In 
SANGUINOLARIA, Lam., 
The hinge is nearly the same as in the wide solens, and has 
two teeth in the middle of each valve, but the valves, which 
are oval, are much closer at the two extremities, where they 
merely gape, as in the mactre. (Solen Sanguinolentus, 
Chemn.) 
PsAMMoBIA, Lam., 
The psammobiz differ from the sanguinolarie in having but 
a single tooth in the middle of one valve, which penetrates 
between two on the opposite one, (Tellina gari, &c.) 
PSAMMOTHEA, Lam., 
But a single tooth to each valve; otherwise resembling the 
psammobize. (Psammothea violacea, Lam., &c.) 
PHOLAS, Lin., 
The pholades have two principal valves, broad and convex 
towards the mouth, narrow and elongated on the opposite 
side, and having a large oblique opening at each extremity ; 
their hinge, like that of a true mya, is furnished with a plate 
projecting from one valve into another, and with an internal 
ligament running from that plate into a corresponding cavity. 
Their mantle is reflected externally upon the hinge, where it 
* 
tc 
