356 THE DESCENT OF MAN 



torn from its body. When several males of a Brazilian 

 Gelasimus, a species furnished with immense pincers, were 

 placed together in a glass vessel by Fritz Mtiller, they 

 mutilated and killed one another. Mr. Bate put a large 

 male Carcinus manas into a pan of water, inhabited by 

 a female which was paired with a smaller male; but the 

 latter was soon dispossessed. Mr. Bate adds, "If they 

 fought, the victory was a bloodless one, for I saw no 

 wounds." This same naturalist separated a male sand- 

 skipper (so common on our sea-shores), Qammarus marinus, 

 from its female, both of whom were imprisoned in the same 

 vessel with many individuals of the same species. The 

 female, when thus divorced, soon joined the others. After 

 a time the male was put again into the same vessel; and 

 he then, after swimming about for a time, dashed into the 

 crowd, and without any fighting at once took away his wife. 

 This fact shows that in the Amphipoda, an order low in 

 the scale, the males and females recognize each other, and 

 are mutually attached. 



The mental powers of the Crustacea are probably higher 

 than at first sight appears probable. Any one who tries to 

 catch one of the shore-crabs, so common on tropical coasts, 

 will perceive how wary and alert they are. There is a large 

 crab {Birgus latro) found on coral islands which makes 

 a thick bed of the picked fibres of the cocoanut, at the 

 bottom of a deep burrow. It feeds on the fallen fruit of 

 this tree by tearing off the husk, fibre by fibre; and it 

 .always begins at that end where the three eye-like depres- 

 sions are situated. It then breaks through one of these eyes 

 by hammering with its heavy front pincers, and, turning 

 round, extracts the albuminous core with its narrow posterior 

 pincers. But these actions are probably instinctive, so that 

 they would be performed as well by a young animal as by 

 an old one. The following case, however, can hardly be 

 so considered: A trustworthy naturalist, Mr. Gardner," 



" "Travels in the Interior of Brazil," 1846, p. 111. I have given, in my 

 "Journal of Researches," p. 463, an account of the habits of the Birgus. 



