78 ZOOPHYTES. 



This is a creature far from being nice in the selection of food. It 

 preys readily and greedily on most animal substances, and the quantities ab- 

 sorbed, are altogether disproportioned to its dimensions. Among the victims 

 of voracity it is singular that living young Actiniae should be acceptable 

 prey, considering their congenerous nature, and the more so, that they seem 

 incapable of making any exertion for self-preservation. In return, the 

 hydra is devoured by the Actinia, — all conform to the general law whereby 

 the weaker among carnivorous animals falls a prey to the stronger. 



When sated, the hydra remains motionless, with the tentacula closely 

 contracted. Judging by the long continued exposure of coloured food 

 through the skin, digestion is probably very slow. If originally copious, 

 the food is rejected by the mouth in a half-digested state, as with the Ac- 

 tinia. Like it also, if sparingly supplied, the whole is apparently absorbed 

 into the system. Sometimes the mass is retained several days, though 

 usually rejected sooner. The residue of a very voracious meal has been 

 retained ten or twelve. 



In farther correspondence with the Actinia, the senses of this hydra, 

 excepting touch, are certainly most obtuse. Hunger merely induces the 

 extension of the tentacula, but there is no evidence that the presence of 

 the prey is discovered, otherwise than by actual contact. No searching 

 activity of the tentacula is shewn even when food is within their reach : no 

 perceptions regarding it are betrayed, unless the action of the lip, as above 

 described, can be an indication ; and although the roots of the tentacula 

 become somewhat more apart, and consequently greater dispersion of their 

 extremities, nothing proves that it is for any important purpose. How- 

 ever, the animal is capable of raising large portions to its mouth ; and its 

 pendent position is clearly the natural one, and for aifording greater scope 

 for the exercise of these flexible organs. 



Speedy increment follows copious sustenance. All hydrse are then 

 rapidly enlarged, attaining tenfold their previous size, if regularly fed ; and 

 they become proportionally prolific. Along with emaciation, the colour 

 fades from- protracted abstinence. 



This is an animal very impatient of the effects of light. While the 

 whole organs are finely displayed in comparative obscurity, they con- 



