400 
STRANGE DWELLINGS . 
One of these nests in my own collection is shaped much like 
one of the halves of a bivalve shell, and is thick at the base 
where it was attached to the rock, diminishing towards the ex- 
tremity. On the outside it has a very shelly appearance, being 
made in regular layers, whose edges are as distinct as those of 
the oyster-shell, but which have a double and not a single curve. 
In shape it is somewhat oval, but the base is necessarily flat, on 
account of its attachment to the rock. 
EDIBLE SWALLOW. 
The material is so translucent, that when placed on printed 
paper and held to the light, the capital letters can be plainly 
read through its substance. A glance at the interior shows 
at once the mode of its construction. It is made of innu- 
