248 Mr. R. Warington on the Natural History 



and allow of its being kept as a store of provision capable of 

 being had recourse to as occasion might require. 



The manner in which these beautiful creatures take their food 

 while foraging about the tank is very interesting. The first 

 and second pair of didactylous feet are cautiously and conti- 

 nuously thrust into every cranny, around and partially under 

 the pebbles and rock-work, and often into the tubes of Serpula 

 or Sabellce, or the shells of the univalve mollusks and others ; and 

 these, if not protected by an operculum or some provision for 

 closing the orifice of their tube or shell, soon fall a prey to their 

 attacks. When anything edible is met with, it is rapidly seized 

 by these prehensile feet and transferred to the jaws. 



The senses of touch and smell in the Palcemonidie are exceed- 

 ingly delicate, the latter appearing to reside most strongly in the 

 antennae. Thus, when a small particle of food has been dropped 

 into the water and has sunk to the bottom, the moment the 

 antennpe of the prawn in its movements pass across the column 

 of water through which the food has fallen, the whole motion of 

 the creature becomes changed in an instant, and it darts rapidly 

 here and there, from the surface throughout the path of its 

 transit until it is discovered; and often, after it has been de- 

 voured by the one, a second prawn will, on reaching the same 

 locality, gain the scent and liunt over every spot in search of 

 that which has been already removed, but which evidently had 

 left its track of odour behind. It has very often occurred, that 

 if some one of the Actinia had been first fed, the Palcemon, on 

 gaining the scent, has tracked the food to the Actinia and 

 speedily rified it of its repast; and, in instances where the latter 

 had even transferred its meal by means of its tentacula to its 

 pouch, the prawn has redoubled its efforts, and frequently 

 dragged the savoury morsel out of its very stomach. This ope- 

 ration it effects in a very surj)rising manner : the Palcemon 

 charges, without any apparent fear, full on the extended disk of 

 the Actinia, the tentacula of which it keeps in constant play by 

 means of its three pairs of unarmed feet, while, at the same time, 

 one of the second or larger pair of prehensile feet is thrust into 

 the orifice of its maw, and the food forcibly and quickly extracted. 

 The only chance the poor Actinia has of preventing this and 

 securing its feast, appears to be by contracting the whole of its 

 tentacula together, and thus forming itself into a small globular 

 form, so as to close entirely all approach to the orifice of its 

 stomach. The energy with which this attack is effected depends 

 very much on the keenness of the prawn's appetite, and, in 

 cases where the Actinia is strong and also very hungry, the con- 

 flict is often very severe, and the aggression is sometimes, though 

 rarely, successfully repelled. 



