HERMIT AND CLOAKLET. 239 



(lower) part of its body, which hue melts into snowy 

 white on the upper parts ; the whole studded with 

 rosy-purple spots, and surmounted by a marginal line 

 of pale scarlet. The tentacles and disk are pure white. 

 It attains a rather large size, and has the peculiarity 

 of being not round in its basal outline like other Ane- 

 mones, but oblong, the base expanding in two lateral 

 directions. It always selects the inner lip of an uni- 

 valve shell for its place of adhesion, and the two 

 lateral ends of its base gradually extend around the 

 mouth of the shell till they meet on its outer edge, 

 and unite with a suture : thus the outline of the 

 animal forms a ring. 



It had often been an interesting speculation with me, 

 in what manner the due relation of size is maintained 

 between the Adamsia and the shell, in the progressive 

 growth of the former. There is a manifest proportion 

 between the two, the young Cloaklet occupying a small 

 shell, such as that of a Littorina or Trochus ; the full- 

 grown individual a large one, such as that of a Natica, 

 or Buccinum. The Crab is able to shift from a smaller 

 to a larger shell when he needs enlarged accommoda- 

 tion ; and since we know that his congener, P. Bernhard- 

 us, does this habitually, we naturally conclude that 

 such is the habit of P. Prideauxii. Presuming then 

 that this is the case, what becomes of the Adamsia ? 



