LAND CEABS 79 



granulated and armed with longitudinal rows of spines. 

 The pleon of the male usually covers the whole space 

 between the bases of the last pair of walking legs. 



These land-crabs are called Toulouroux by the French. 

 They inhabit the warm territories of both hemispheres. 

 The third maxillipeds suffice without other details to dis- 

 criminate the genera. 



Uca, Leach, 1817. The third maxillipeds have the 

 fifth joint attached at the outer angle of the fourth ; 

 the inner edges of the third and fourth joints are 

 in one line ; along their outer edges the exopod is 

 externally visible, and has a nagellum. 



Gecarcinucus, Milne-Edwards, 1842. The third maxilli- 

 peds have the fifth joint attached to the middle of 

 the apical margin of the fourth ; the inner edges of 

 the third and fourth joints are in one line ; the 

 exopod as in Uca. 



Cardisoma, Latreille, 1825. The third maxillipeds 

 have the fifth joint attached at the outer angle of 

 the fourth ; the inner edges of the third and fourth 

 joints form a re-entering angle ; the exopod as in. 

 Uca. 



Gecarcoidea, Milne-Edwards, 1837. The third maxil- 

 lipeds have the fifth joint inserted in a deep groove 

 of the apex of the fourth ; the inner edges of the 

 third and fourth form a re-entering angle ; the 

 exopod is without flagellum and concealed beneath 

 the third joint. 



Gecarcinus, Leach, 1815. The third maxillipeds have 

 the fifth joint attached on the inner margin of the 

 fourth and completely concealed by it ; the inner 

 edges of the third and fourth joints form a re- 

 entering angle ; the exopod as in Gecarcoidea. 



Hylceocarcinus, Wood-Mason, 1874. The third max- 

 illipeds have the fifth joint attached to the middle 

 of the apex of the fourth ; the inner edges of the 

 third and fourth form a re-entering angle ; the 

 exopod as in Gecarcoidea. 



