CLASS-BOOK OF ZOOLOGY. l7l 



the size of the fist, varying in color from blue to red. 

 Along the back is a very delicate membrane for sailing, 

 which the animal, when swimming, inflates with air. 



§ 749. The Round-worm (Ascaris Lumbricoides) is the 

 most common of human intestinal worms, found princi- 

 pally in the small intestines, and sometimes in vast num- 

 bers. 



$ 750. It is generally as thick as a quill, nearly one 

 foot long, and of a whitish color ; it is oviparous, and is 

 found also in cows, hogs, and horses. 



§ 751. The Tape-worm (Taenia) comprises a large 

 number of different species. It is notable as well for the 

 peculiarity of its structure as for the injury it does to the 

 human body, and the tenacity with which it clings to it. 



§ 752. This worm is articulated, and attaches itself by 

 means of the pointed proboscis projecting from its head 

 with four lobes. Next to the head is a small and almost 

 thread-like neck, the joints of which become gradually 

 larger as they approach the body. In each of the larger 

 joints is an ovary, from which the eggs escape. 



QUESTIONS ON SECT. XLV. 



741. What are Long-bodied Worms? 



742. Describe the Leech. 



743. What injury do they do, and for what are they used ? 



744. How can they be raised ? ■ 



745. Describe the Earth-worm. 



746. What do you know of its saddle ? 



747. What do you know of its reproductive power and increase ? 



748. Describe the Portuguese Man-of-War. 



749. Which is the most common human intestinal worm ? 



750. Describe the Round-worm. 



751. For what is the Tape-worm notable? 



752. Describe the Tape-worm. 



LIST OF SOME WORMS. 

 1st Order. — Gelatinous Worms. 



1. The Monade. 



2. " Proteus. 



3. " Wheel-animal. 



4. w Blossom-polype. 



5. " Hydra. 



6. « Sertularia. 



7. The Plume-polype. 



8. « Sea-fig. 



9. " Common Sea-blubber or 



Sea-nettle. 

 10. " Purple Sea-nettle. 



