158 CLASS-BOOK OF ZOOLOGY. 



SECTION XLI. 



Is* Order — Gelatinous Worms : (Zoophyta, Lin.) 



§ 670. Among the Gelatinous Worms may be men- 

 tioned the Infusory Animalcules, which are the lowest 

 and smallest of living creatures. Their body is nothing 

 but a stomach with a mouth, and can only be seen by 

 means of a microscope which magnifies more than one 

 hundred times. 



\ 67 1 . These animalcules are to be found in immense 

 numbers in any fluid in which organic substances have 

 been decomposed. One single drop will present hun- 

 dreds of them, resembling little balls, moving about at 

 pleasure ; whilst others of a larger size and different form 

 will be seen swimming like whales among them. 



\ 672. The green slimy substance, found on water- 

 plants, posts, and stones, will also furnish a great variety 

 of them. 



\ 673. That they are real animals, is evinced by the 

 power they possess of moving in all directions ; and by 

 their taking food, which they effect, by bringing the 

 water around them into a whirl by a rapid motion of the 

 hair at their mouth, into which other still smaller animal- 

 cules are drawn. 



§ 674. The smallest of these animals is the Monada, 

 which is round like a ball, and may not exceed the thou- 

 sandth part of a line ; and the largest is the Wheel-animal, 

 half a line long, which is found upon the leaves of the 

 Water-crowfoot, as well as other water-plants. 



§ 675. The Polypes are gelatinous, living contractile 

 tubes, with arms as thin as a human hair, by which they 

 seize their prey. 



§ 676. Their food consists, according to their size, of 

 Infusory Animalcules, small Crabs, Earthworms, Fishes, 

 or tender water-plants. 



§ 677. They are found in large numbers on water- 

 plants, in all stagnant waters, and can easily be obtained 



