WORMS, ROTIFERS, LEECHES, POLYZOA 91 



beautiful fresh-water forms, to be met with in streams and lakes ; 

 but the most numerous and interesting forms are dwellers in the 

 sea. As regards their exact position in the animal kingdom, 

 opinions are somewhat divided, some zoologists considering them 

 as related to the Mollusca, others to the Worms. The latter view 

 has the support of such able embryologists as Agassiz, Steen- 

 strup, Morse, and Kovalevsky, and is now the more generally 

 accepted. 



