264 



THK DESCENT OF MAN. 



rivals; but this will not account for their inequality in the fe- 

 male on the opposite sides of the body. In Gelasimus, according 



Fig. 5. Anterior part of body of Callianassa (from Milne-Edwards), 



showing the unequal and differently constructed right 



and left-hand chelae of the male. 



N. B.— The artist by mistake has reversed the drawing, and made 

 the left-hand chela the largest. 



Fig. 6. 



Fig, 7. 



Fig. 6. Second leg of male OrchestiaTucuratinga (from Fritz Muller). 

 Pig. 7. Ditto of female. 



to a statement quoted by Milne-Edwards," the male and the fe- 

 male live in the same burrow, and this shows that they pair; 

 the male closes the mouth of the burrow with one of its chelae, 

 which is enormously developed; so that here it indirectly serves 

 as a means of defense. Their main use however, is probably to 



Soc' ISC:', p. 363; and on the nomenclature of the genus, ibid. p. 585, 

 I am greatly Indebted to Mr. Spenoe Bate for nearly all the above 

 statements with respect to the chelae of the higher crustaceans. 

 " 'Hist. Nat. des Crust.' torn, ii, 1837, p. 50. 



