304 
SUPPLEMENT 
before the fire in cold water, while alive, for were they to be 
thrown into the liquor already boiling, the moment they felt 
the strong impression of the heat, they would break their 
claws, the preservation of which is a necessary condition in 
the art of cooking them. When put to the fire in the cold 
water, they seem to perish without feeling any pain intense 
enough to cause violent movement or agitation. 
In the large rivers of Russia, such as the Don and the 
Volga, there are astaci of prodigious size, which are never 
fished but lor the sake of getting the stones above mentioned. 
When a certain quantity have been taken, they are heaped 
together to cause them to rot, and when their decomposition 
is almost complete, they are washed with water. The stones, 
as being the most heavy, fall to the bottom. These stones, 
which, for many ages, have enjoyed a very high reputation, 
and which are still considerably sought after in countries 
where prejudice and superstition predominate, are no longer 
esteemed in Europe, but as a little bit of chalk, and if it may 
still be found in the shops of some apothecaries, it is merely 
from a remnant of ancient custom. 
The various species of sea astaci have vulgar names, dif- 
fering from the scientific, in consequence of an error of Lin- 
nmus. Thus the lobster, {homard, in French) is not the 
cancer homarus of this naturalist, but the cancer mar in us. 
The cancer homarus is a part of the genus Palinurus, of 
which we shall presently speak. 
We shall next briefly notice that very curious genus the 
Pagukus. 
The Greeks named generically carcinion, the parasite Crus- 
tacea, which lodge themselves in the empty shells of the 
mollusca, and the Latins designated these same animals under 
a synonymous name cancelli. Aldrovandus, Gesner, Rondelet, 
Swammerdam, and other modern naturalists, preserve this last 
denomination ; but Fabricius lias bestowed that of Pagurus 
