HYDRA.' 23 



The Hydra are fresh water animals of very diminu- 

 tive size, and are generally fixed to some solid body, as 

 a stick or leaf, by the tail, though they have the power 

 of detaching themselves and of moving slowly through 

 the water. They are carnivorous animals, and though 

 they do not chase their prey, they devour all kinds of 

 living creatures coming within reach of their tentacula, 

 which they can manage. Worms longer than them- 

 selves they devour, by first doubling them together by 

 means of their long arms. 



A Hydra in the act of gorging a 

 worm of twice its own size is seen at 

 fig. 9. The poor worm is completely 

 entangled within the folds of the ten- 

 tacula, while the voracious animal, with 

 expanded mouth is absorbing its juices, so as to bring it 

 within the capacity of himself. 



It sometimes happens that when two of these animals 

 have siezed the same worm by different ends, a violent 

 struggle ensues between them, and the stronger, having 

 gained the victory,- not only swallows the object of con- 

 Fig. 10. tention, but his antagonist along with it. 

 Fig. 10 represents such a case, the tail of 

 the swallowed animal protruding from the 

 mouth of the victor. But the former soon 

 extricates himself from this dilemma, without 

 having suffered the least injury, and indeed is 

 often the gainer, by retaining a portion of the 

 object of contention to himself. 

 But the most singular, and indeed, astonishing facts 

 which Mr. Trembley ascertained with respect to these 

 animals, are, that they have the power of repairing all 

 sorts of injuries and mutilations inflicted on them, and of 

 still digesting their food, and of recovering a good de- 

 gree of health after being turned wrong side out. 



If their tentacula be clipped off they soon grow again. 

 If the animal be cut in two, across the middle, there 

 will sprout forth a new head from one part, and a new 

 tail from the other, together with such portions of the 

 body in each case as were wanted to make a good and 



What is said of the power of the hydra to reproduce mutilations 1 



