Chap. XII. Reptiles. 351 



the sexes unite. 51 With the huge tortoise of the Galapagos 

 Islands (Testudo nigra) the males are said to grow to a larger 

 size than the females: during the pairing-season, and at no 

 other time, the male utters a hoarse bellowing noise, which can 

 be heard at the distance of more than a hundred yards ; the 

 female, on the other hand, never uses her voice. 52 



With the Ttstudo elegans of India, it is said u that the combats 

 " of the males may be heard at some distance, from the noise 

 " they produce in butting against each other." 53 



Crocodilia. — The sexes apparently do not differ in colour; nor 

 do I know that the males fight together, though this is pro- 

 bable, for some kinds make a prodigious display before the 

 females. Bartram C4 describes the male alligator as striving 

 to win the female by splashing and roaring in the midst 

 of a lagoon, " swollen to an extent ready to burst, with its 

 " head and tail lifted up, he spins or twirls round on the 

 " surface of the water, like an Indian chief rehearsing his feats 

 of war." During the season of love, a musky odour is emitted 

 by the submaxillary glands of the crocodile, and pervades their 

 haunts. 55 



Ophidia.—Dr. Gunther informs me that the males are always 

 smaller than the females, and generally have longer and slenderer 

 tails ; but he knows of no other difference in external structure. 

 In regard to colour, he can almost always distinguish the male 

 from the female by his more strongly-pronounced tints ; thus 

 the black zigzag band on the back of the male English viper is 

 more distinctly defined than in the female. The difference is 

 much plainer in the rattle-snakes of N. America, the male of 

 which, as the keeper in the Zoological Gardens shewed me, can at 

 once be distinguished from the female by having more lurid 

 yellow about its whole body. In S. Africa the Bucephalus 

 capensis presents an analogous difference, for the female "is 

 " never so fully variegated with yellow on the sides as the 

 " male." 56 The male of the Indian Dipsas cynodon, on the 

 other hand, is blackish-brown, with the belly partly black, 

 whilst the female is reddish or yellowish-olive, with the belly 

 either uniform yellowish or marbled with black. In the Tragopt 

 dispar of the same country, the male is bright green, and the 



»'• Mr. C: J. MaynaTd, 'The British India,' 1864, p. 7. 

 Arreriean Naturalist,' Dec. 18G9, p. 54 ' Travels through Carolina, 



$55. &c -> 1791, p. 128. 



52 See my ' Journal of Researches "Owen, 'Anatomy of Verte- 

 Juring the Voyage of the " Beagle," ' brates,' vol. i. 1866, p. 615. 



845,'p. 384. 56 Sir Andrew Smith, ' Zoolog. of 



53 Dr. Gunther, ' Reptiles of S. Africa :• ReptiKa,' 1849, pi. x. 



