BEACHIOPODS AND POLYZOANS. 

 BRACHIOPODS. 



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These mollusks have the two valves of unequal size, 

 and in one of them there is a hole through which passes 



Figs. 459. — Terebratula, — a Brachiopod. Fig. 460. — Brachiopod. 



Fig. 461. — Lingula, — a Brachiopod. Reduced. Philippines. 



a fleshy stalk, by which the shell is attached to the 

 rocks. The word Brachiopod means arm-footed, and is 

 given to these animals on account of the long, fringed 

 arms growing from the sides of the mouth, and by 

 means of which they make currents in the water and 

 thus secure their food. 



POLYZOANS. 



These are very small or minute mollusks, growing 

 in clusters upon shells, rocks, and other objects, both 

 in the sea and in fresh waters, and which look very 

 much like Polyps. They are often called Bryozoans. 



Dr. Leidy and Captain Hyatt have described and 

 beautifully figured many of our fresh-water kinds, and 

 we hope you will some time see and read their inter- 

 esting and instructive papers. 



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