OGRE BIVALVE  _MOLEUSKS 89 
Although not quite so delicious as the oyster, 
the Mya is an excellent food-mollusk, and is sold 
in San Francisco 
in immense quan- 
tities. Its do- 
mains are not 
fenced in, like the 
oyster fields, but 
it may be gath- 
ered by anybody 
who will take the 
trouble. Figure 
79 gives a view 
of the inside of a left-valve, showing the spoon- 
like hinge-tooth, the muscle-sears, and the pallial 
sinus. ‘The valves are rather thin and brittle; they 
gape at the ends, and the edges are covered with 
a gray epidermis. The common length of grown 
specimens is three inches. 
Mya truncata, Linn., the Blunt Mya, resembles 
the last, but the siphon end is truncated, as if it 
had been chopped off. This species also lives in 
the Atlantic, and is reckoned as cireumboreal, com- 
ing down on the west side as far as Puget Sound. 
Cryptomya californica, Conr., the False Mya, 
lives all along the coast. The shell is elliptical, 
shghtly gaping, nearly smooth, sometimes marked 
with faint lines. The sinus is small or obsolete, 
and the right valve is provided with a large, spoon- 
shaped hinge-tooth, on which is the ligament. Shell 
rather thin, white, with ashy epidermis; length 
an inch or more. 
