SOMETHING ABOUT POLYPES. o9 



Linnaeus considered our little friends as forming an intermediate class between 

 the two kingdoms; but as the wisest sometimes err, "the Prince of Naturalists" 

 was mistaken J and though his theory was peculiarly fanciful, Ellis's more 

 accurate statements have superseded it. Enough has been said here of their 

 history as a class, and of their advocates. 



To return to the Hydra, whose home is in almost every pond or ditch. 

 Among the duck-weed and other watei'-plants, it may be easily procured by 

 those who wish to observe for themselves its form and habits. The most 

 common species is the Ht/clra viridis, so small, that when stretched out, it 

 looks like a little piece of green sewing-silk, but if the magnifying glass is 

 used, it will be seen that the body is a little gelatinous bag with an opening 

 at one end, which is its mouth, surrounded with seven delicate tentacles; at 

 the opposite end nature has provided it with a flattened disc, by which it can 

 attach itself to any fixed body, or move, though with extreme slowness, from 

 one place to another. When disturbed, it contracts its body to an almost 

 invisible speck, although no trace of muscles can be discerned in its composition. 

 Its favourite position is suspending itself from some floating plant, and a still 

 more novel mode of locomotion, which it sometimes employs, is to protrude 

 its sucker above the water, hollowed out like a boat, possessing sufficient 

 buoyancy to enable our Hydra to sport where he pleases by means of his 

 tentacles, in readiness to secure whatever his appetite might fancy; and 

 extremely carnivorous is he in his propensities; — animals, much larger and 

 stronger than himself, fall a prey to his voracity; this is owing to the 

 benumbing power possessed by his arms, which is so strong as to prevent the 

 escape of the poor victim that has once been stiicken by him. Larvae of 

 insects, worms, and the tiny Crustaceans, called Entomostraca, are his favourite 

 food, and these being most abundant in every place where the Hydra dwells 

 he is able to satisfy his desires; but it has been proved that he can endure 

 a fast for many weeks and still live on. It is well that he possesses this 

 stupifying power over his prey, for it is by a very slow process that he brings^ 

 the food to his mouth; tentacle after tentacle lends its aid to assist, and by 

 sure efforts accomplish their purpose. 



But the most wonderful part in the history of the Hydras is the power 

 which they have of multiplying their species; the most usual method is by 

 means of buds, which sprout from some part of the surface of their bodies; 

 at first the bud is shapeless, but soon it assumes the form of the parent 

 animal, developing tentacles around the oral aperture. It remains attached ta 

 the body of the parent for some time, until it is perfect in all its parts,^ 

 when it is cast ofi", and, in its turn, becomes the mother of a numerous 

 progeny. "Trembley noticed that by snipping the side of an adult Polype 

 with the points of a fine pair of scissors, a bud would soon develop itself from 

 the wounded part, and this experiment was repeated until as many as seven- , 

 teen had been obtained, all connected with each other, and thus forming a 

 little tree of living Polypes." The Hydra will occasionally divide into twoi 



