136 ARTHROPODA 



The blood of the crayfish, like that of the insects, is color- 

 less. After circulating through the arteries and their 

 branches to carry oxygen and nourishment to all parts of 

 the body it collects in irregular channels, called sinuses, 

 lying between the muscles and the other organs. From 

 the sinuses, vessels lead the blood to the gills on either side 

 beneath the carapace to absorb oxygen from the surround- 

 ing water and give off the carbon dioxide collected from 

 the tissues of the body. From the gills the blood returns 



FJG. 157. Photograph of the lobster one third natural size. 



to the pericardial sinus and enters the heart through six 

 slits with valves opening inward. 



The lobster (Homarus americanus') ranges along the 

 Atlantic coast from Labrador to Delaware Bay. Of late 

 years it has become so scarce that laws have been passed 

 for its protection. In Connecticut none may be caught 

 under six inches long, while in New York and Massachu- 

 setts they must be not less than ten and a half inches in 

 length. At Cold Spring Harbor, Long Island, and at 

 Woods Hole, stations have been established by the govern- 

 ment for the purpose of rearing young lobsters. The eggs, 



