54 THE ZOOLOGIST. 



I think I may claim to have had opportunities for observation of 

 some value. 



As a rule, two Crabs will not live together for long in a small 

 aquarium. Sooner or later they will have a desperate battle, and 

 the weaker will get killed. In one case I rescued the vanquished 

 mcenas before he had lost his life. He was in a parlous state, 

 having lost both his claws and three of his legs. I transferred 

 him to a small inverted propagating glass, and carefully fed 

 him ; much as one feeds a baby with a spoon, so did I put 

 morsels of scraped beef on to his mandibles with a wooden 

 skewer. He used the foremost of his remaining feet to push the 

 food into his mouth, reminding me of an armless man I saw in 

 a show at Cambridge Fair who fed himself with his toes. He 

 was in this miserably crippled condition for weeks. At last 

 came the time for the exuviation of his shell ; then, lo ! as by a 

 miracle, he appeared straightway with his full complement of 

 legs and two pairs of claws, just as if nothing had happened. 



The day before the Crab exuviated there had not been a 

 vestige of claw to be seen or of the three vanished legs. There 

 was no sign whatever of sprouting and gradual growth. When 

 the old shell was cast off the new limbs grew as quickly as do the 

 wings of a butterfly or moth when released from the chrysalis- 

 case ; they grew so quickly that I did not see them grow. One 

 hour the Crab had no claws and only five legs ; in the next, when 

 I again noticed him, he was soft and flaccid, but with every one 

 of his limbs quite perfect. The new shell rapidly hardened, and 

 the next day the Crab was using his new claws just as if he 

 had never lost them. I put the exuviated shell in my little 

 museum, and when the Crab exuviated again I put by the side of 

 it the newly-formed shell with the full complement of claws 

 and legs. 



Out of the many specimens of Carcinus mcenas I have had under 

 observation I have never noticed a single instance of a new limb 

 sprouting out and growing gradually in the manner I have seen 

 described in books. A lost limb has always been instantaneously, 

 as it were, reproduced at the time of exuviation. 



Yet sometimes we meet with Crabs of the edible species 

 having one large and one small pair of pincers and claws. 

 Personally, I have only met with one instance of this. In that 



