296 



PROTECTION OF YOUNG 



There is very little care of the young among the lower animals 

 such as frogs and fishes. In many cases the parent dies before 



the egg has had time to hatch. 

 The fertilized eggs are usually 

 left unprotected. In an occasional 

 species there is some evidence of 

 what may be called parental care. 

 For example, in some fishes, the 

 parent may find a protected spot, 

 as under a rock, and lay a mass 

 of eggs. The salmon and other 

 fish that spend part of their lives 

 in salt water and part in fresh 

 water, migrate many miles up large 

 rivers and deposit eggs in shallow 

 water far from their natural en- 

 Yet, of the one or two 

 1 by each female, 

 only a very few will ever reach 

 maturity. Among the crustaceans 

 (lobsters, crabs, shrimps) the female sometimes produces a sticky 

 fluid about the eggs. As the eggs come out of the body and be- 

 come fertilized, they are at- 

 tached to the swimmerets on 

 the abdomen of the female 

 and remain there until the 

 embryos are ready to hatch. 

 Among the mollusks (oysters 



. . , .,. j The. female crayfish not only carries her eggs 



and Clams) the fertilized eggS attached to the swimmerets, but by straightening 



.,i . ,, ., p her abdomen and waving the swimmerets brings 



remain Within the Cavity Ot the eggs in contact with a supply of oxygen. 



the mother's mantle and so 



are protected by the shell until the young hatch and are able to 



swim. 



Museum of Natural History 

 The female lobster carries the eggs while 



emies. 



they are developing. Special hairs attached 'II' ^O-O-Q 

 to the appendages of the abdomen secrete nillllOn CggS 

 a sticky substance which holds the eggs in 

 place. This secures protection. 



