222 



ZOOLOGY 



state similar to the taproot which has lost water by osmosis) so 

 that the muscles can be drawn through without injury. The 

 lobster also molts a part of the lining of the digestive tract as 

 far as the posterior portion of the stomach. Immediately after 

 molting the lobster is in a helpless condition, and is more or less 

 at the mercy of its enemies until the new shell, which is se- 

 creted by the skin, has grown. This process takes several weeks 

 to complete. 



Economic Importance. — The lobster is highly esteemed as 

 food, and is rapidly disappearing from our coasts as the result of 

 overfishing. Between twenty million and thirty million are yearly 

 taken on the North Atlantic coast. This means a value at present 

 prices of about $15,000,000. Laws are now enacted in New York 

 and other states against overfishing. Egg-carrying lobsters must 

 be returned to the water, all smaller than six to nine 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. Some states now hatch and care 

 for the young for a period of time; the United States Fish Com- 

 mission is also doing much good work, in hope of restocking to 

 some extent the now almost depleted waters. 



Shrimps. — Several other common crustaceans are near relatives 

 of the crayfish. Among them are the shrimps and prawns, 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 fishes, they do not appear to be 



decreasing in numbers. Be- 

 sides this value as a food, 

 they are also used by man, 

 the shrimp fisheries in this 

 country aggregating almost 

 $1,000,000 yearly. 



The Blue Crab. — Another 

 edible crustacean of consid- 

 erable economic importance 

 is the blue crab. Crabs are 

 found inhabiting muddy bot- 



The edible blue crab. From photograph loaned 

 by the American Museum of Natural History. 



