268 Adjustment to Conditio)! s of Aquatic Life 



The water-fleas and many of our rotifers are hibernating 

 as winter eggs. The bryozoans and sponges are hiber- 

 nating as statoblasts. Doubtless many of the simpler 

 organisms whose w T ays are still unknown to us have their 



Fig. 167. Ceriodaphnia, molted skin and liberated ephippium 

 of the same individual shown in the preceding figure. This 

 photograph was taken only a few minutes after the other. 

 The female after molting immediately swam away. 



own times and seasons and modes of passing a period of 

 rest. It is doubtless due, also, to the ease and safety 

 with which they may be transported when in such 

 condition that they all have a wide distribution over the 

 face of the earth. In range, they are cosmopolitan. 



