ADAPTATION OF STRUCTURE TO HABIT. 47 



loped, and the antennse are much longer than the body ; 

 while in general conformation and structure it bears 

 the closest affinity with another Crustacean, found 

 commonly in the same haunts, which from the form 

 of the carapace and the free abdomen, every one would 

 immediately pronounce to be a Lobster ; and it is so 

 named by the common people, I refer to the little 

 "Dutch Lobster" fGalathea squamifera). 



Let us now look at the manner of life of the little 

 Crab, and we shall discover some interesting relations 

 between its habits and its conformation. I have said 

 that it inhabits crevices, and the under-sides of stones. 

 As soon as it is dropped into the Aquarium, it throws 

 out its abdomen, or " tail ;" and gives several smart 

 flaps with it, which shoot it along diagonally back- 

 wards, as if to say, "Though you see I am a Crab, I 

 have learned to behave myself in some things like my 

 courtly Cousins, the Lobster family." But he is not 

 much of a swimmer, the flaps merely bring him to the 

 bottom slantwise, instead of perpendicularly, whence 

 he does not rise again. You turn your head away, 

 and on looking again you cannot think what is be- 

 come of your Broad-claw ! I have put in half-a-dozen 

 at a time, and have been astonished that in a few 

 moments, not one w^s to be seen ; till, perhaps weeks 

 afterwards, on cleaning out the tank, I have found 

 every one clinging fast to the under side of some 

 piece of stone that lay on the bottom. When I knew 

 this, I placed flattish stones so close to ths glass sides 

 that I could look beneath them, and had the pleasure 

 of finding them occupied by the Broad-claws. The 

 crevice formed by the inclination of the stone to the 



