CLASS-BOOK OF ZOOLOGY. 169 



oval crustaceous body, according to the species, is one or 

 several inches long, white or rose-colored, and is generally 

 called Sea-egg, on account of its form. 



§ 735. Its crustaceous body is covered with a skin, 

 containing nearly 2,000 prickles, which, as its skin is 

 moveable, enable it to creep at the bottom of the sea. 



§ 736. These prickles are an inch and more long, not 

 thicker than a fine needle, shining and pointed, brittle as 

 glass, and of a brown or black color. 



§ 737. The Eatable Sea Hedge-hog (Echinus escu- 

 lentus) is about as large as a man's hand, and is the only 

 species that is used as food. The part eaten is the ovary, 

 (receptacle of eggs,) which, when boiled, is considered a 

 great delicacy. 



§ 738. The Sea-star (Asterias) has a cartilaginous body 

 in the form of a star, consisting generally of five points, 

 which are covered with short prickles. By means of 

 these they move in the same manner as the Sea Hedge- 

 hog, but with less speed. 



§ 739. In the upper part of its body is a wide mouth, 

 near which is a stomach, connected with intestines ex- 

 tending through the rays. 



§ 740. The reproductive power of this animal is very 

 remarkable. If the rays be cut off they will grow again ; 

 and if cut into several pieces, each piece becomes a new 

 Star-fish. 



QUESTIONS ON SECT. XL1V. 



733. What are Prickly Worms? 



734. Describe the Sea Hedge-hog. 



735. By what means does it creep? 



736. Describe its prickles. 



737. What is the size and the use of the Sea Hedge-hog? 



738. Describe the Sea-star. 



739. What do you know of its internal construction? 



740. What can you say of its reproductive power? 



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