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it is striped longitudinally with light color. Sometimes the stripes run 

 transversely in bands or spots. It is found from New Jersey northward 

 on rocky shores of bays and sounds, or in eel-grass on sandy shores. 



I. ochotensis. A species very similar to the preceding, but a little 

 larger, found on the Pacific coast. 



I. metattica. This species is a little smaller than I. marina, and dif- 

 fers from it in having the end of the telson truncated, or straight, instead 

 of dentate. The head is nearly square. The body is broadest in the 

 middle of the thorax ; the projecting epimera give a serrate appearance 

 to the sides. The abdominal feet are inclosed in the operculum-like 

 scales of the first pair of feet. Its color is bright blue or green, often 

 with a metallic luster when seen in the water. It is found swimming 

 free or floating in masses of seaweeds from Long Island northward and 

 also on the Pacific coast. 



I. wosnesenskii. A common species on the California coast, about 

 one inch long and dark in color. The abdominal segments are united 

 and bluntly rounded, and each has a small median tooth. The abdomi- 

 nal feet are inclosed by the opercular 

 feet. Eggs and young are carried in a 

 pouch. 



GENUS Chiridotea 



C. cteca. This species burrows be- 

 neath the surface of the sand, raising it 

 up into a little ridge, and makes a 

 mound at the end of the burrow, where 

 it may be found. These trails are 

 common on the wet sand. It imitates 

 the sand in color, and is about half an 

 inch in length, with a broad thorax and 

 narrow abdomen terminating in a point. 

 It is found on the New England coast. 



C. entomon (Linnaeus). This species 

 of the northern Pacific coast is from one 

 to three inches long. The head has the 

 appearance of two lobes, the sides hav- 

 ing two rounded ends. The body is 

 broad, the abdomen narrowing to a 

 pointed end. The last segments of the abdomen are united, and the 

 abdominal feet are inclosed by the first pair, which extend over them 

 like an operculum. The epimera are broad, with acute lateral angles. 



Chiridotea casca. 



CLASS MERISTOMES 

 OEDER XIPHOSURA 



GENUS Limulus 



L. polyphemus, the horseshoe- or king-crab. This well-known and 

 curious animal ranges along the Atlantic coast from Maine to Mexico. 



