350 



ECONOMIC IMPORTANCE OF ANIMALS 



sters must be returned to the water ; all smaller than six to ten and 

 one half inches in length (the law varies in different states) must be 



put back ; other restrictions are placed 

 upon the taking of the animals, in hope 

 of saving the race from extinction. Such 

 states now hatch and care for the young 

 lobsters for a period of time ; the United 

 States Bureau of Fisheries is also doing 

 much good work, in the hope of restock- 

 ing to some extent the now almost 

 depleted waters. 



Several other common crustaceans are 

 near relatives of the crayfish. Among 

 them are the shrimp and the prawn, 

 thin-shelled, active crustaceans common 

 along our eastern coast. In spite of the 

 fact that they form a large part of the 

 food supply of many marine animals, 

 especially fish, they do not appear to be 

 decreasing in numbers. They are also 

 used as food by man. 



Another edible crustacean of consider- 

 able economic importance is the blue 

 crab. Crabs are found inhabiting muddy bottoms ; in such local- 

 ities they are caught in great numbers in nets or traps baited with 

 decaying meat. They are, in- 

 deed, among our most valu- 

 able sea scavengers, although 

 they are hunters of living prey 

 also. The young crabs differ 

 considerably in form from the 

 adult. They undergo a com- 

 plete metamorphosis. Imme- 

 diately after molting or shed- 

 ding of the outer shell in 

 order to grow larger, crabs 

 are known as '' shedders," or soft-shelled crabs. 

 greatly desired by man as an article of food. 



North American lobster. 

 This specimen was of unusual 

 size and weighed more than 

 twenty pounds. 



American Museum of Natural History. 



The edible blue crab. 



They are then 



