236 STALK-EYED CRUSTACEA 



The members of this family are the land-crabs, 

 properly so called. They usually live in holes in the 

 ground, made by themselves either in the damp mud on 

 the water edge, or in dry banks a long way from water. 

 They make the hole by forcing the four walking legs on 

 the side opposite the large hand into the ground, and, 

 by keeping those legs together, forming a scoop, they 

 walk out of the hole by the aid of their other four walking 

 legs and carr)^ out all that the scoop formed by the first 

 mentioned legs holds. 



When the ground so excavated becomes heaped up at 

 the mouth of the tunnel they flatten it by sitting on the top 

 of the heap and moving the first pair of legs from them, 

 so pushing the accumulation of earth away. They appear 

 to notice the approach of strangers by the vibrations of 

 the ground. 



SvNorsis OF THE Genera. 



A. The fifth and following joints of the ^ , — . 

 external maxillipedes are completely hid P^^l^'") 

 behind the fourth joint. — {Geocarcinus?) ^. ^^^^ ' 



B. The fifth and following joints of the ^"'""^'''""■ 

 external maxillipedes are not hid behind the 

 fourth joint. 



a. The fifth joint of the external maxilli- 

 pedes is inserted in a deep notch in the 

 summit of the fourth ]omt.—{Gecarcoidea.) Gccanoidca. 



b. The fifth joint of the external maxillipedes is 

 inserted at the external angle of the fourth joint. 



b'^. The third and fourth joint of the 

 external maxillipedes do not close com- 

 pletely the buccal cavity, but leave a 

 rhomboidal space between their internal \\ 

 edges. — ( Cardiosoina.) Cardiosoma. 



