FIRST LESSONS IN ZOOLOGY 



will recall the sea-urchins and starfishes and sea-anemones 

 which live in the tide-pools. On the beach, too, there 

 are innumerable shells, each representing a dead ocean 

 animal. But more abundant than all of these, and in 



one way more important 

 than all, are the myriads of 

 the marine Protozoa. 



Although the water at 

 the surface of the ocean ap- 

 pears clear, and on super- 

 ficial examination seems to 

 contain no animals, yet in 

 certain parts of the world 

 (especially in the southern 

 seas) a microscopical exam- 

 ination of it sho\\s it to be 

 swarming with Protozoa. 

 And not only is the water 

 just at the surface inhabited 

 by one-celled animals, but 

 they can be found all the 



Fin. 83,-6-/™/„r sp. ; a p„.;„zoan Way dowD to a great depth, 

 wliich may be fixed, like Voriicclla, In a pint of ocean water 



(tr free-swininiiiig. at will, anil . , .... 



whieh has the nucleus iu the shape there may be millions of 

 of a striuK or chain of bead-like these minute animals. In 



bodies. The figure shows a single 



individual as it appeared when fixed, the OCeans of the world the 



with elongate stalked body, and as number of them is inconceiv- 



It appeared when swimming about, 



with contracted body. (Greatly able. And it is necessar}' 



magnified; from life. ) 4-I t il ^^ 4. ■ ^ ■ 



that these 1 rotozoa e.xist in 

 such great numbers, for the)' and the marine one-colled 

 plants (Protophyta), supply directly or indirectly the food 

 of all the other animals of the ocean. 



Among these ocean I'roto/oa there are numerous kinds 

 with the body inclosed in a minute shell (fig. 84'). These 

 tiny shells present a great variety of shape and pattern. 



