114 
tion of their birth can never know a parent’s care 
and teaching, to employ the same means to the 
same ends with unerring accuracy. Among the 
mollusca, many make the bodies of other living ani- 
mals serve them for a nest. Of the order intestina, 
ascarides, taenia, &c. above 200 species breed in the 
viscera of almost all the species of other animals. 
The tznia bufonis in the toad, the fasciola loliginis 
in the cuttle-fish. The habitations wrought from 
the secretion of their own bodies by the order tes- 
tacea, univalves, bivalves, and multivalves, are too 
well known to need particular mention, too nu- 
merous to admit of detailed description in this place, 
and too beautiful to be overlooked by those who 
have the slightest curiosity to regard either graceful 
varieties of form or harmonies of colour. 
In the cardita concamerata there is however an 
inner chamber within the exterior shell, in which 
the eggs are actually deposited and hatched. Many 
of the testacea form clustered grape-like balls: for 
example, the buccina, commonly found among sea- 
weed on our shores; others form strings of discs 
closely connected by a single point of their edge, 
near to which the eggs are deposited, like seeds 
under the scales of fir cones: such, I believe, are 
nides of the murex, purpura, &c. The helix vivi- 
para may be noticed as a species which hatches its 
young within the shell. 
It may be said that shells are not nests. This is 
true for the most part, if the term est be limited 
by definition to mean a place for the deposit merely 

