262 DIMYARIA,—UNIONIDA. 
have been before alluded to. (See ante, p. 43.) 
Such cases, however, are rare, and, as Pennant 
remarks, for one who is affected by eating mussels, 
a hundred remain uninjured. In general, they are 
simply boiled with us; but probably they might 
be made much more savoury by a different mode 
of cooking. Captain King, in speaking of a large 
species (JZ. choros) found abundantly on some 
islands on the Pacific coast of South America, 
observes :—‘‘ The manner in which the natives of 
these islands, both Indians and descendants of 
foreigners, cook shell-fish is similar to that used 
for baking in the South Sea Islands, and in some 
parts of the coast of New Holland. A hole is 
dug in the ground, in which large smooth stones 
are laid, and upon them a fire is kindled. When 
they are sufficiently heated, the ashes are cleared 
away, the shell-fish heaped upon the stones, and 
covered first with leaves or straw, and then with 
earth. The fish thus baked are exceedingly tender 
and good, and this mode of cooking them 1s supe- 
rior to any other, as they retain within the shell 
all their own juiciness.” 
Famity UNIONIDZ. 
(Freshwater Mussels.) 
From the true Mussels the transition is easy to 
those of this family. They are distinguished 
chiefly by the structure of the foot of the animal, 
which is greatly developed in dimensions, and, at 
least in general, has not the power of spinning a 
byssus. Mr. Anthony, however, a conchologist of 
the United States, where the great abundance of 
