296 POPULAR HISTORY OF THE AQUARIUM. 



end and a mouth at the other, surrounded by a circle of 

 retractile tentacles or feelers. Like Actinias, they are 

 capable of collapsing the entire body into a little knob or 

 button, and then, again expanding, they spread out their 

 feelers to search for prey, which consists of minute insects and 

 small worms. The touch of their feelers partly paralyzes 

 their victims, which are swallowed entire and digested in 

 the stomach. This is not their only movement, for they 

 can crawl something in the manner of some caterpillars, by 

 bringing the two extremities of the body together, making 

 a bow in the middle, then moving the head a pace and 

 bringing up the hinder disc to it. Like some plants, they 

 are propagated either by buds or cuttings; the former, of 

 course, the most natural. A little bud is seen at the side 

 of the full-grown polype, it increases, it puts forth its 

 circle of tentacula, and after a few days separates from the 

 parent and becomes independent. The other method of 

 propagation is the result of those curious and perhaps not 

 really cruel experiments which originally caused so much 

 excitement among naturahsts. The Hydra may be divided 

 and subdivided into a great number of parts ; and each part 

 will, under favourable circumstances, become a new polype. 

 If the head be cut off, a few days will give a new body to 



