THE INTKHDEI'llNDENCE OF MV|\(; ril|\(;s 



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Stickleback and nest. Of what advantage would this be to the species? 



mals survive this dangerous stage, their chances of growing to adults 

 are very considerable. Although parental care is not associated 

 with plants, nevertheless in low forms of plant lif(> locomotor stages 

 occur, called zoospores or swarm spores, by means of which the plants 

 gain footholds in new areas. Many devices have already been men- 

 tioned by means of which seeds are scattered far from the parent 

 plant. In higher plants, hard shells, spiny coverings, or inedible pulp 

 protect seeds within the mature fruit, thus giving greater ojjpor- 

 tunity for the scattering and germination of seeds. 



Adaptations for the protection of young are more evident among 

 animals. In crustaceans, the larvae of which form the chief food 

 for great numbers of fish, there are not a few protective adaptations. 

 In some instances crustaceans have brood pouches in which the young 

 are kept, or, as in the case of crayfish and lobster, the developing 

 eggs are cemented to the abdominal appendages of the mother and 

 carried around by her. The male bullhead .swims arountl with and 

 broods over his young, while the male sea horse has a brood pouch in 

 which the young are held. In some worms and crustaceans, the eggs 

 may be retained in the burrow of the parent, or they may be held 

 in the mantle cavity or a space similar to it, as in the fresh-water 

 mussels, barnacles, and tunicates. Some spiders, notably the wolf 

 spiders, carry the egg cocoon about with them and when the yoimg 

 are hatched, they are carried on the backs and legs of the female 



