A " HANGER-ON." 



119 



soft abdominal portion of its body is safely tucked away, 

 and screened from prying eyes. Nor is it ever withdrawn, 

 until the crab, finding its shelter too small for its require- 

 ments, voluntarily relaxes its hold ; and having selected 

 a more commodious dwelling-house, cannily proceeds 

 to inserfc its hinder-parts into it and take up a fresh lease. 



As in the true crabs (Brachyura), the first pair of legs 

 belonging to Cenohita have been modified into big claws 

 or chelipeds ; but, contrary to what is seen in our familiar 

 table friend, one of these has become enormously developed 

 as compared with its fellow. Both claws are used for 

 seizing food and breaking it up ; but the larger one, in 

 addition to serving the hermit-crab as a formidable means 

 of offence, serves it also as a means of protection ; for by 

 first withdrawing the fore-part (cephalo-thorax) of its 

 body, it can finally block up the mouth of the shell with 

 this big claw and so can bid defiance and afford to laugh 

 at its enemies outside. 



These hermit-crabs on Swan Island ranged from mere 

 brats to giant fellows which were living in the shells of a 

 common gasteropod mollusc, the magpie trochus, called 

 by scientists Livona pica. Woe betide the unfortunate 

 individual who, in his zeal to procure bait, happened to 

 have his fingers or thumb pinched by one of the big claws 

 of these last grown-up members of the race ; for they have 

 a bulldog's tenacity of hold, combined with a crushing 

 power which is extremely effective from the crab's point 

 of view, but horribly painful for the bait procurer, A 

 " tip " worth knowing in a predicament of this nature, 

 is immediately to place the hand or finger, which has been 

 seized, on the ground. The crab then instantly lets go. 

 So long as you hold your hand up with the crab dangling 

 in mid-air, it hangs on like grim death. 



Mr. Borradaile (" Proceedings of the Zoological Society") 

 says that the bodies of the hermit-crabs of this genus 

 may be physiologically divided as regards their outward 

 aspect into three regions : a fore-part, a mid-part, and a 

 hind-part. 



