ENTOMOSTRACA AND PHYLLOPODA. 241 



egg masses are carried about by the parent, and are con- 

 spicuous objects. It is a common occurrence to find 

 the little animals apparently loaded with the burden of 

 eggs, and not uncommon to see the young escape. The 

 " common Cyclops" is an instance. No member of the 

 Entomostraca is so frequently seen and so abundant as 

 the Cyclops, and hardly any other affords so good an 

 example of this method of depositing and caring for 

 the eggs in external ovaries, Cyclops having two of the 

 latter, while some other almost equally common forms 

 have but one. The external ovaries are usually long, 

 pear-shaped bodies attached to the rear of the animal, 

 near where it diminishes to form its tail -like portion. 

 The eggs are round, unless they are made polygonal by 

 pressure, almost black, and entirely opaque. In Cantho- 

 camptus there is but one external ovary. Both kinds 

 are shown in Figs. 166 and 167. 



The young, when first hatched, bear so slight a re- 

 semblance to the parent that some of them have been 

 described and named as entirely different animals ; and 

 it was not until they were seen leaving the egg while 

 still attached, or in the external ovary, that their true 

 character was discovered. This is especially true of 

 Cyclops. The young animal is shown in Figure 1670. 

 It changes its skin several times before it begins to re- 

 semble its mother, a similar peculiarity being noticeable 

 in many of the Entomostraca. 



These little crustaceans are found in almost every 

 body of still water. Some prefer the surface, where, on 



