102 THE LIFE OF CRUSTACEA 



The members of the tribe Hippidea (sometimes 

 called "Mole Crabs"), among the Anomura, have 

 habits somewhat similar to those of the Crabs just 

 described. They are common on sandy beaches in 

 the warmer parts of the globe, and they burrow with 

 great rapidity by means of the curved, flattened 

 end-segments of the legs. The carapace is generally 

 smooth and oval, and the body is compact, the short 

 abdomen being folded up as in the Crabs. 



In Albunea (Plate XIV.), which belongs to this 

 tribe, a long " antennal tube," which looks very like 

 that of Corystes, is believed to have a similar func- 

 tion in connection with respiration when the animal 

 is buried. In this case, however, the tube is formed, 

 not by the antennae, as in Corystes, but by the anten- 

 nules, so that it affords a striking example of the 

 independent evolution of similar structures from 

 quite different origins. 



Hippa emerita, which is found on the coasts of 

 North and South America, has the mouth parts 

 imperfectly formed, and not adapted for biting ; and 

 it is stated by Professor S. I. Smith that the animal 

 feeds in the way that an earthworm does, swallowing 

 the sand through which it burrows, and extracting 

 the nutriment which it may contain. This habit, 

 however, is not followed by other members of the 

 tribe, for Mr. Borradaile found that a species of 

 Remipes in the Maldive Islands could " easily be 

 caught by a bait of Crab at the end of a line, 



