144 ENTOZOA. TART in. 



SECTION V. 



ANNULOSA, OR WORMS. 



THE Amrulosa, which are the lowest grade of articu- 

 lated animals, consist of four distinct orders: the En- 

 tozoa, which are muscle and intestine parasites; the 

 Turbeltariee, fresh and salt-water animals covered with 

 cilia ; the Annelida, or Worms ; and the Rotifers, or 

 Wheel animalcules. 



Entozoa. 



There are three genera and numerous species of 

 Entozoa. Every animal has one or more species peculiar 

 to itself; fourteen infest the human race. They have 

 a soft, absorbent body of a white or whitish colour, in 

 consequence of being excluded from light, and living as 

 they do by absorbing the vitalized juices of the ani- 

 mals they infest. Their nutritive system is in the lowest 

 state of development ; yet there are some of a higher 

 grade. All are remarkable for their vast productive- 

 ness. 



The Tsenioidse, which belong to the inferior group, 

 are intestinal, many-jointed worms, which have neither 

 mouth nor digestive organs ; and what is called the 

 head has only hooks and suckers to fasten it to the 

 internal membrane of the animal at whose expense it 

 lives. The common Tsenia, or Tape-worm, sometimes 

 ten feet long, which is the type of the order, has four 



