2 SEXUAL SELECTION. Part II. 



smooth. They are only temporarily developed during 

 the breeding-season ; and Dr. Giinther suspects that they 

 are brought into action as prehensile organs by the 

 doublin<>: inwards and downwards of the two sides of the 

 body. It is a remarkable fact that the females and not 

 the males of some species, as of Baia clavata, have their 

 backs studded ^^ith large hook-formed spines.^ 



Owing to the element which fishes inhabit, little 

 is known about their courtsliip, and not much about 

 tlieir battles. The male stickleback (Gasterosteiis lei- 

 urus) has been described as " mad with delight " when 

 the female comes out of her hiding-place and surveys 

 the nest which he has made for her. '* He darts round 

 *' her in every direction, then to his accumulated ma- 

 *' terials for the nest, then back again in an instant ; 

 " and as she does not advance he endeavours to push 

 " her with his snout, and then tries to pull her by the 

 " tail and side-spine to the nest." ^ The males are said 

 to be polygamists f they are extraordinarily bold and 

 pugnacious, whilst " the females are quite pacific." 

 Their battles are at times desperate ; " for these puny 

 " combatants fasten tight on each other for several 

 " seconds, tumbling over and over again, until their 

 " strength appears completely exhausted." With the 

 rough-tailed stickleback ((r. irachurus) the males whilst 

 fighting swim round and round each other, biting and 

 endeavouring to pierce each other with their raised lateral 

 spines. The same writer adds,* " the bite of these little 



' Yarrell's ' Hist, of British Fishes,' vol. ii. 1836, p. 417, 425, 436. 

 Dr. Giinther informs me that the spines in B. clavata are peculiar to the 

 female. 



2 See Mr. E. Warington's interesting articles in ' Annals and Mag. 

 of Nat. Hist.' Oct. 1852 and Nov. 1855. 



' Noel Humphreys, ' River Gardens,' 1857. 



" Loudon's ' Mag. of Natural History,' vol. iii. 1830, p. 331. 



