ox 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 

 one-handed. They have 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 



