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SUPPLEMENT 
still more a reservoir, in which there have been none before. 
Few aquatic animals are more delicate respecting the nature 
of the water in which they are to live ; after being transported 
in this way, they have been observed to come out of the 
water and die upon land. It is especially when they are 
taken from running water, and put into stagnant, that this 
phenomenon is observed, although this water be not mortal to 
them, since they are often naturally to be found therein. 
The only waters which are really mortal to them, are those 
which are in an actual state of putrefaction. 
The astaci, like all the other Crustacea, live only upon 
animal substances. It is most probably in consequence of 
incorrect observation, that they have been said to eat veget- 
ables ; every thing in the animal way is to their taste, whether 
living or in a state of corruption. In case of famine, and 
especially when they change skin, they will eat one another. 
Small fish, small mollusca, the larvae of insects, and every 
thing that is drowned in the waters, form the basis of their 
subsistence in the summer season. They remain during the 
entire winter without eating, or almost without eating any 
thing. They have, as enemies, almost all the animals which 
frequent the waters, or which constantly inhabit there, such 
as otters, water-rats, aquatic birds, voracious fishes, and even 
the larvae of insects. Nevertheless, as they multiply greatly, 
and the number of their enemies diminishes as they advance 
in age, that is to say, when they acquire strength, it is suf- 
ficient to avoid fishing for some years, in a stream nearly ex- 
hausted of them, and to keep watch upon the otters and 
herons, to have as many there as in the first instance. 
The sea astaci are fond of rocky coasts, and rocks, in the 
fissures of which they can conceal themselves. They are 
found in almost all seas, and are by no means rare upon the 
coasts of Europe. Some individuals attain to a gigantic size ; 
not a few have been seen three feet in length. 
