It means that more life is going on than merely keeping alive and being re- 

 placed. As in differentiation of structures and functions in vegetative life, 

 the specialization seems to yield more than it costs. 



In What Ways Do Animals Care for Their Young? 



Infancy among Animals^ Among most of the lower animals the mother 

 lays large numbers of eggs — in the water, on leaves, in the soil — and abandons 

 them. But toward the upper end of many series of animals we find that the 

 parents supply much more for the young. The lobster and crayfish mothers 

 carry the eggs about on their abdominal legs, or swimmerets, and they carry 

 even the young embryos until they are able to care for themselves (see illustra- 

 tion below). Among the insects some species abandon their eggs as soon as 

 they are laid, whereas others supply shelter and food for the young. 



In some species of toads the father places the fertilized eggs in his mouth 

 and keeps them in his croaking pouches until the tadpoles are large enough to 

 swim away. Several species of newts and salamanders guard the developing 

 young within the body of the mother until the young are fully formed and able 

 to shift for themselves. 



^See Nos. 1 and 2, p. 432. 



*~»((K-J- ''■««?»»«;51pSW™f^-S(^» 



United Slates Fish and^Wildlife Service 



A "BERRIED" LOBSTER 



420 



