Chap. IX. 



Crustaceans. 



267 



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

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



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

 equal and diifeiently-coustructcd right and leit-hand chelai of the male. 



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

 the largest. 



Fig. 6. 



Fig. t. 



Fig. 6. Second leg of male Orchefitia Tucuratinga (from Fritz Miiller). 

 Fig. 7. . Llitto of female. 



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

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

 and size that they cannot possibly be used for carrying food to the 

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

 the right leg is actually longer than the whole body.'" The 

 gr iat size of the one leg with its chete may aid the male in 

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



'" See a paper by Mr. C. Spence 

 Bato, with figures, in ' Proc. Zoolns;. 

 Soc' 1H68, p. 363 ; and on the 

 nomenelature of the genus, ibid. p. 



585. I am greatly indebted to Mr. 

 Spence Bate for nearly all the above 

 statements with i-espect to the chelae 

 of the higher crustaceans. 



