CEABS. 233 



Lobster it constitutes a large proportion of the body, and is 

 free, the tail being broadly expanded and used as a flapper. 

 Between these therefore there are intermediate forms, such 

 as Galathea, which has its abdomen free in swimmhig, but 

 habitually tucked close under the body, like a crab when at 

 rest. The Hermit Crab likewise has the abdomen long and 

 cylindrical, but ill-formed, and kept wound round the colu- 

 mella of a shell. 



The metamorphoses or changes of condition undergone 

 by Crustacea have already been spoken of. They take place 

 at successive stages before maturity, each stage bringing 

 them nearer to their ultimate form. As in the immature, 

 or Zoe state, the tails of Crabs as well as Shrimps and 

 Lobsters are free, there is much less difference between 

 them than when mature. In fact, they are all shrimp-like 

 in form. But they have sessile eyes, i'.e. eyes not elevated 

 upon stalks. 



The following observations on the " sloughing '' of this 

 species are taken from Sir J. Dalyell. That gentleman had 

 kept for some time a specimen of Carcimis mcEuas, of medium 

 size, of a brown colour, with one white limb. " One summer 

 evening it was put outside the window in a capacious glass 

 vessel of sea- water. In the morning, a form exactly resem- 



