36 THE NATURAL HISTORY OF THE COMMON CRAYFISH. 
that the carapace is raised, nothing stops the crayfish 
from continuing its struggles. Iftaken out of the water 
in this condition, they go on moulting in the hand, and 
even pressure on their bodies will not arrest their efforts. 
The length of time occupied from the first giving way 
of the integuments to the final emergence of the animal, 
varies with its vigour, and the conditions under which it 
is placed, from ten minutes to several hours. The 
chitinous lining of the stomach, with its teeth, and the 
‘‘ erabs’-eyes,” are shed along with the rest of the cuti- 
cular exoskeleton ; but they are broken up and dissolved 
in the stomach. 
The new integuments of the crayfish remain soft for 
a period which varies from one to three days; and it is 
a curious fact, that the animal appears to be quite aware 
of its helplessness, and governs itself accordingly. 
An observant naturalist says: ‘I once had a do- 
mesticated crayfish (Astacus fluviatilis), which I kept in 
a glass pan, in water, not more than an inch and a half 
deep, previous experiment having shown that in deeper 
water, probably from want of sufficient aération, this 
animal would not live long. By degrees my prisoner 
became very bold, and when I held my fingers at the 
edge of the vessel, he assailed them with promptness and 
energy. About a year after I had him, I perceived, as I 
thought, a second crayfish with him. On examination, 
I found it to be his old coat, which he had left in a most 
perfect state. My friend had now lost his heroism, and 
