Chap. IX. 



Crustaceans. 



26/ 



body, and by the inequality being much greater in the male than 

 in the female ; and why, when they are of equal size, both ars 



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

 equal and differently-constructed right and left-hand chela? of the male. 



N.B— The artist by mistake has reversed the drawing, and made the left-hand chela v 

 the largest. 



Fig. 6. 



Fig. 1. 



Fig. 6. 



Fig. 7. 



Second leg of male Orchcstia Tucuratinga (from Fritz Miiller). 

 Ditto of female. 



often much larger in the male than in the female, is not known. 

 As 1 hear from Mr. Bate, the chelae are sometimes of such length 

 and size that they cannot possibly be usecTfor carrying food to the 

 mouth. In the males of certain fresh- water prawns (Pal Demon) 

 the right leg is actually longer than the whole body. 10 The 

 great size of the one leg with its chelae may aid the male in 

 lighting with his rivals; but this will not account for their 



10 See a paper by Mr. C. Spence 

 Bate, with figures, in ' Proe. Zoolog. 

 Soc' 1868, p. 363 ; and on the 

 nomenclature of the genus, ibid. p. 



585. I am greatly indebted to Mr. 

 Spence Bate for nearly all the above 

 statements with respect to the chelae 

 of the higher crustaceans. 



