THE ENTOMOLOGIST. 61 
I have called it, varies infinitely in its character: in the 
larve of Lepidoptera it is thin, soft, and flexible in the 
extreme; while in crustaceans, particularly in the claw of an 
aged crab, it is so thick, solid, and calcareous, that it can 
only be broken by a smart blow with the hammer. Between 
these two opposites of extreme thinness and extreme thick- 
ness, every conceivable intermediate occurs; but whatever 
difference exists in this respect all exo-skeletons agree in 
being repeatedly shed and renewed during life-time. The 
process of moulting is common to most animals: the bird 
loses and reproduces its feathers; the suckler its hair; but 
in exosteates this exuviation extends to the whole covering: 
this is shed entire, and not only to the covering, for the 
exuviation extends to the interior, but those organs which 
are most intimately connected with life share the same fate 
as the exo-skeleton, of which they actually seem to form part, 
and are cast off like our old clothes and replaced by a new 
suit. [have been particularly interested in observing how 
complete is this internal, as well as external, exuviation in 
crabs, crayfish, and lobsters, the discarded garments of which 
form most beautiful objects to examine, showing that even 
the breathing apparatus to its most minute parts is cast off, 
and replaced by a new one secreted within the body of 
the animal. [These are the Articulata of Cuvier. ] 
3. Anosteate animals, which have no bones at all, but 
which have the power of building a house or shell for 
protection out of material secreted by their own body. I say 
have the power of doing so; but they do not always exercise 
the power, very many species having neither bone, shell, nor 
any substitute for these at any period of life. [These are the 
Mollusca of Cuvier. } 
4. Actiniate animals, which have their several organs 
arranged in a radiating fashion round a centre, like the star- 
fish. The other divisions have not this radiating arrange- 
ment of parts, but are what is called bilateral, that is, they 
have both sides alike. [These are the Radiata of Cuvier.] 
The second of these divisions is that to which the sawflies 
belong; but these require further division. 
In my Familiar Introduction, published in 1841, I adopted 
Latreille’s name of Condylopa for this province, but 1 now 
prefer to propose an entirely new one—Evosteata ; its contents 
