157 
PHOLAS prisons. 
TAB. DLXXXI. 
Spec. Char. Oblong oval, finely striated; striae 
smooth, transverse ; anterior extremity round- 
ed very short, with a deep angular sinus in its 
edge, becoming closed by shell when old; 
posterior extremity truncated ; beaks covered 
by an accessory valve ; a series of scales form 
a longitudinal band nearly in the middle of 
each valve. 
A small species, very similar to P. clavata of Lamarck 
and others, that dwell in holes they form in wood. 
The anterior side is very small ; its edges near the 
beaks are reflected and covered by a heart-shaped valve. 
In the young state of the animal the sinuses in the valves 
form a rhomboidal opening, which in the adult is closed 
by a smooth continuation of the shell. 
For the discovery of this highly interesting Fossil we 
are indebted to H. H. Goodhall, Esq. Wood penetrated 
