OK CRUSTACEA. 
281 
and observing that they were spread over a considerable ex- 
tent of shore, where they appeared altogether at home in their 
habits, plunging under water if they were out of it, concealing 
themselves also under stones, &c. and showing a great degree 
of vivacity, I no longer doubted that they were then in their 
element, and that on the other hand they would find them- 
selves very ill at ease, if they were carried into the salt-water. 
It also appeared to me that these fresh-water crabs were more 
cunning and more alert than those of the sea, which allow 
themselves to be taken with facility. I could not catch the 
former but by drawing them towards the shore with the end 
of my stick, which was not easy, so well did they know how 
to steal away. They also defended themselves vigorously 
when they could do no better; and I could perfectly well feel, 
from the force with which they strained the stick between 
their claws, that it would not be safe to take them with my 
hand. A fisherman, whom I found on re-ascending, also in- 
formed me that they drew blood. He confirmed me in the 
opinion that these crabs were perfectly natural in this lake, 
and that they were known there always. But he added, that 
they withdrew during winter into the bottom, and did not re- 
appear upon the banks until summer. He added likewise 
that they were very excellent eating.” 
The Crustacea of the genus Gelasimus are similar to the 
ocypodes, in the general form of the body and in habits. One 
of their most striking characters is the extraordinary dispro- 
portion in the length of their claws : one, sometimes the right, 
sometimes the left, for this varies in individuals of the same 
species, is enormously large, while the other is very small, and 
often concealed. One would say that these animals were 
. x e the habit of raising the thickest of 
these claws in the air, as if they wished to make a signal, and 
call somebody. For this reason, Linnaeus has designated one 
