INVERTEBRATA. 427 



dermata, Entozoa, Acalepha, (or sea-nettle,) Polypi, includ- 

 ing the sponges and Infusoria, or the "microscopic inhabitants 

 of stagnant waters." Among this group are the single-cell 

 animals, to which allusion has been made as the simplest 

 form of animal. The mountain has many representatives 

 of this great division of the animal kingdom, from the order 

 Nematoidea, of more complicated structure, to the simple 

 Infusorial orders, Rotifera and Homogenea. 



