72 THE AQUARIAN NATURALIST. 



is shown even when food is within their reach; no 

 perceptions regarding it are betrayed, unless the ac- 

 tion of the proboscis above alluded to can be regarded 

 as of this character. However, when prey is seized, 

 the animal is capable of raising large portions to its 

 mouth, and its pendent position is clearly the natural 

 one, affording the greatest scope for the play of its 

 flexible tentacula. 



This is an animal very impatient of the effects of 

 light. While all the organs are finely displayed in 

 comparative obscurity, they contract quickly on re- 

 moval to the light, and always as if to avoid some 

 painful impression. 



The power of adhesion is probably spontaneous, as 

 with the freshwater Hydra and the Actinise of the 

 seas; but the Hydra tuba commonly remains sta- 

 tionary where it has taken a position. If affixed at 

 first to the bottom of a vessel, it remains permanently 

 there. If it drops from its place when attached to 

 the side, or should the water be repeatedly agitated 

 while either adults or young are loose, they seldom 

 adhere afterwards, nor does the animal fix itself readily 

 at any time. 



A locomotive faculty, though rarely exercised, and 

 only in the lowest degree, is undoubtedly enjoyed by 

 these creatures. The adult is never seen in the act 

 of progression, but the young Hydra withdraws itself 

 from the parent, and in the event of successive gene- 

 rations, all the individuals constitute a colony around 

 its original founder. Thus the perceptive and active 

 faculties of these creatures are exceedingly obtuse, 

 imperfect, and limited, farther than belongs to seizing 



