173 
MYA intermedia 
TAB. LXXVI.—Fig. I. 
Serc. Cuar. Depressed, smooth, twice as wide as 
long, sides rounded, anterior side expanded, 
gaping a little; posterior side small; front 
carly straight. 
- i 
ening of the gaping side is less extravagant than in 
ost Mya; the general flatness of the shell, but particularly 
»' the anterior side, distinguish this in its external appearance 
(rom severai fresh-water shells of the Genus Mya of Linz. or 
Unio of De Lamarcke and others. The specimens in general 
are about two inches and an half wide. I was favoured 
with some by Lady Wilson, as well as by Mr. Borrer from 
Bognor. I venture to consider it a Mya, but I could not 
see the hinge with so much certainty as I could wish, 
although I had many specimens, as the valves are generally 
closed and held strongly together by the tough sandy marle. 
The shell is a little chalky, but breaks in some parts with 
a brittle and angular fracture. 
MYA plana. ; 
TAB. LXXVI.—Fig. 2. 
Spec. Cuar. Rather depressed, smooth, wider than 
long, ovate, nearly equilateral; anterior side 
rather elongated; front rounded. 
en 
Tus is a very delicate, slender shell; the anterior side 
scarcely gapes, but is slightly truncated only: about three- 
fourths of an inch wide. 
