56 THE ZOOLOGIST. 



with, and grows very large before its final exuviation — if it ever 

 leaves off moulting at all until it dies. I do not like to hazard a 

 guess as to the length of life to which it will attain. I have seen 

 more than one which, judging by the rate of growth of those I have 

 had under observation, must have been considerably older than 

 I am. Not one of my aquaria is large enough to contain speci- 

 mens of the size which those I have kept might have grown to if 

 they had had more room. They require far more water than the 

 Shore Crab does. The latter I have kept fairly successfully in 

 cages with just a pan of sea-water for them to bathe in, but the 

 Edible Crab will die unless wholly immersed, and is not happy 

 unless the water is deep, and in plenty. I only wish it had been 

 my good fortune to have had charge of the tanks in the Crystal 

 Palace Aquarium or at Brighton. I should have enjoyed nothing 

 better. In such deep tanks as these the Edible Crab is at 

 its best. 



Other species of Crabs which I have kept with more or less 

 success have been the Swimming Crabs (Portumnus) — very inter- 

 esting crustaceans, but needing larger aquaria than mine. My 

 largest tank was five feet long by two deep, and twenty inches wide. 

 I was not able to work out the life-history of these Crabs so 

 thoroughly as in the case of the shallow water Crabs. Then 

 I have had the long-armed Masked Crabs (Corystes cassivelaunus) , 

 very interesting to me as being living representatives of some 

 I used to find fossil in the Cambridge greensand, and labelled 

 Notopocorystes bechei. 



Not the least interesting of my Crabs have been the Hermit 

 Crabs. It is most comical to see them change from one domicile 

 to another. A curious trait in their character is that they seem 

 to like company. To name them after a monk is singularly 

 inappropriate to those who know how fond they seem to be 

 of the society of creatures lower than themselves in the scale 

 of life. The association between the "Hermit" Crab and the 

 Cloaklet Anemone is well known, but I had a Pagurus which 

 permitted a large Nereis to live with it in a Whelk- shell and 

 share its food. It neither quitted the shell in disgust nor tried 

 to kill the intruder, as it might easily have done when the worm 

 came half out of the shell. 



Then I have kept the long-legged Spider Crabs and the 



