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SUPPLEMENT 
Sciences, has collected the following observations respecting 
this animal. 
“ It was on the 28th day of July, 1812, that I had occasion 
to see and observe this curious crustaceum, on visiting the 
celebrated dcgorgeoir of the Lake of Albano, otherwise the 
Lake of Castello. It is known that the basin of this lake is 
considered by most travellers, and even naturalists, to be 
the crater of an ancient volcano. It is five miles in circuit, 
and as much as four hundred and eighty feet of depth is 
given to the water which fills the lower part. This water 
is limpid, perfectly sweet, and is inhabited by divers kinds 
of fresh-water fish, common frogs, &c. The redundancy 
of water runs off incessantly in a great stream by this ad- 
mirable subterraneous canal, which is almost two miles 
long, and which has been preserved, without deterioration, 
from the earliest times of Rome. The heat which reigned in 
the atmosphere when I was in this part of the country, the 
purity of the water, the solitude, the shade, and freshness of 
the shore, the bottom of which could be discovered there, to 
a ver J great distance from the edge, like a strand, induced me 
to bathe, and it was thus that I chanced to catch three or four 
individuals of the species of crab in question. 
“I was very much surprised at the first appearance of these 
crabs, not being by any means prepared for it. They ap- 
peared to me so similar in figure, size, gait, &c. to those 
which are commonly found on maritime shores, in fine, to the 
Cancer mamas , that I imagined at first that they might be 
those identical crabs, which had been brought from the sea, 
which is not, in fact, very distant, as an attempt to naturalize 
them in this lake, and that this attempt had succeeded. 
Nevertheless, I remarked that they had a whitish or livid 
colour, whereas the marine ones to which I was comparing 
them are brown. Afterwards, perceiving scattered here and 
there some carapaces, and other old remains of these crabs, 
