92 ENTOZOA. FILIARIA. 



parent, and frequently presents traces of annular divisions. 

 Trie mouth occupies its anterior extremity, and on each side, or 

 around it, are seen the vibratory cilise (fig. 81, #), the rotatory 

 movements of which are very remarkable. The mouth is fur- 

 nished with powerful muscles and lateral jaws. The digestive 

 canal expends from one end of the body to the other, and ordi- 

 narily has an enlargement near the middle which constitutes the 

 stomach (c) ; on each side of this tube are frequently seen bodies 

 of a glandular appearance, and at its posterior extremity a sort 

 of cloaca into which the oviducts empty. 



CLASS OF ENTOZO'A. 



7. This division comprises intestinal worms and other inferior 

 animals of similar organization. Intestinal worms bear a closer 

 resemblance to anne'lidans than to ordinary radiate animals. The 

 body is elongated and composed of more or less distinct rings ; 

 there is often a digestive canal, sometimes vesse,s, but never a 

 distinct circulation or special organs of respiration. 



8. Most of these singular creatures can live only in the bodies 

 of other animals, and lodge themselves in the substance of the 

 liver, in the eyes, in the cellular tissue, in the muscles, and even 

 in the brain, as well as in the alimentary canal ; we know they 

 are multiplied by means of eggs, and also that their young are 

 in some instances born alive, but we do not understand by what 

 means they are transmitted from one animal to another, nor how 

 they penetrate into the substance of organs in which they are 

 developed. There is scarcely an animal that does not nourish 

 many kinds of them, and those found in one species are rarely 

 found in many others. 



9. This class is divided into two orders : one in which the 

 intestinal canal floats free in the cavity of the abdomen, and 

 therefore denominated cavifa'ria ; the other is named parenchy'- 

 mata, because the animalcules of this order have neither abdo- 

 men nor intestine distinct from the neighbouring parts, their 

 digestive cavity consisting of ramified canals hollowed out in the 

 substance of the body, and generally opening externally by 

 suckers. 



10. To the first division belong the FILIA'BLA ; they have a 

 slender, filiform body ; several species are known, which live in 

 the substance of the organs of many animals. One of these is 

 the Guinea-worm ; it lodges itself beneath the skin of man, and 



7. What description of animals belong to the class of Entozo'a ? 

 8 Where are these animals found ? 

 9. How is the class of Entozo'a divided ? 

 10. What are filia'rirt ? What are asca'rides? 



