Handbook of Paleontology 131 



green. The Toad Crab is a Spider Crab, the common- 

 est one along the New England coast north of Cape 

 Cod. It spreads over two and one-half inches. The 

 body is relatively large, the legs slender and weak, 

 and the back and legs are often densely covered with 

 seaweed planted by the crab itself. This crab crawls 

 over rocky bottoms in deep waters but it is abundant 

 in shallow, rocky tide pools from the Arctic ocean to 

 Xew Jersey. It forms an important part of the food 

 of cod. Little crustaceans also are to be sought in 

 our pools under stones and seaweed. Among these 

 are the little Beach Flea (Orchestia agilis) and the 

 Scud (Gammarus locusta) which resembles the former 

 but is much larger. In both these small crustaceans 

 the body is flattened laterally. The Beach Flea is 

 about half an inch in length and of a brown color that 

 much resembles decaying seaweed. When disturbed 

 it jumps with great agility and strength. It ranges 

 from Xew Jersey to Greenland. The Scud is much 

 larger, sometimes attaining a length of one and a half 

 inches. It is reddish or olive-green in color and has 

 the same range as the Beach Flea. There are other 

 species of Gammarus, some slate color. 



Rocks and rocky bottoms support a great variety of 

 life, but the character of the association, particularly 

 between tide marks, depends upon the degree of ex- 

 posure. No other habitat is subject to such a wide 

 range of fluctuation in environmental conditions as rock 

 beaches, and the fauna is composed largely of animals 

 that are either small and ubiquitous, active and hard- 

 shelled, permanently attached or with well-developed 

 clinging organs. The Rockweeds, Common Edible 

 Mussels, Limpets and Acorn Barnacles have shapes 



