802 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 thej 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 

 incoiTect 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 larva) 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. 



