72 HISTORY OF BRITISH CRUSTACEA. 



prowess, and each, finding the other armed at all points, re- 

 tires ; but not unseldoin, a regular passage of arms ensues ; 

 the claws are rapidly thrown about, widely gaping and 

 threatening, and the combatants roll over and over in the 

 tussle. Sometimes, however, the aggressive spirit is more 

 decided and more ferocious. One in the Aquarium of the 

 Zoological Gardens was seen to approach another, who 

 tenanted a shell somewhat larger than his own, and, sud- 

 denly seizing his victim's front with his powerful claw, drag 

 him like lightning from his house, into which the aggressor 

 as swiftly inserted his own body, leaving the miserable suf- 

 ferer struggling in the agonies of death." * 



When the P. Bernhardus is the tenant of the whelk- 

 shell, it is a common thing to find the spire occupied as the 

 seat of the Actinia parasitica, a fine animal-flower. Mr. 

 Gosse has observed that this association is not the only one 

 that exists. " While I was feeding one of my soldiers, by 

 giving him a fragment of cooked meat, which he, having 

 seized with one claw, had transferred to the foot-jaws, and 

 was munching, I saw protrude, from between the body of the 

 Crab and the whelk-shell, the head of a beautiful worm, 

 Nereis bilineata, which rapidly glided out round the Crab's 

 * Gosse, Aquarium, p. 163. 



