266 Adjustment to Conditions of Aquatic Life 



The accompanying figures illustrate both kinds of 

 eggs in the water-flea, Ceriodaphnia, an inhabitant of 

 bottomland ponds. Figure 165 shows a female with 

 the summer eggs in the brood chamber on her back. 

 These thin-shelled eggs are greenish in color. They 

 hatch where they are and the young Ceriodaphnias live 



Fig. 165. Ceriodaphnia, with summer e£ 



within the brood-chamber until they have absorbed all 

 the yolk stored within the egg and have become very 

 active. Then they escape between the valves of the 

 shell at the rear. 



Winter eggs in this species are produced singly. 

 Figure 1 66 shows one in the brood chamber of another 

 female. It is inclosed in a chitinized protective cover- 



