294 MARINE INVERTEBRATES 
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. metallica. 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 ina 
pouch. 
Genus Chiridotea 
C. ceca. 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 
iuch in length, with a broad thorax and 
narrow abdomen terminating in a point. 
It is found on the New England coast. 
C. entomon (Linneus). 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- 
Ohiridotea ceca. 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. 
CLASS MERISTOMES 
ORDER 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. 
