196 THE MICROSCOPE. 



tentacula ; alimentary canal variable ; where there is an intestine, the 

 anus opens near the mouth ; asexual ; gemmiparous ; aquatic. The in- 

 dividuals (Polyps) of a few families are separate and perfect in them- 

 selves ; but the greater number of Zoophytes are compound beings, viz. 

 each Zoophyte consists of an indefinite number of individuals or polyps 

 organically connected, and placed in a calcareous, horny, or membranous 

 case or cells, forming by their aggregation corals, or plant-like Polypi- 

 doms * * which is the house or support of the polyps ; and which, 

 though commonly present, is yet not necessary to the existence of a 

 Zoophyte." 



Opposed to all our common ideas of animal life is this singular 

 creation. If we cut a limb off a tree, or sever that of an animal, these 

 parts will wither and decompose, by passing into other forms of matter. 

 Cut a tree across its middle, and its natural symmetry is irreparably 

 disfigured ; slit it down its centre, and it is destroyed : all animals so 

 treated suffer instant death, with the sole exception of the polyp ; for 

 it will put forth new limbs, form a new head or tail, and if slit, become 

 two separate existences. 



fig. 104. 



Hydra, with its tentacles displayed and magnified, adhering to a stalk of the 

 Anacharis. 



The animals of the first order, the Hydroida, are generally com- 

 pound, and invested with a horny tubular polypidom; the digestive 



