30 
SEXUAL SELECTION. 
Part II. 
In the Tragojps disbar of the same country, the male is 
bright green, and the female bronze-coloured . 50 No 
doubt the colours of some snakes serve as a protection, 
as the green tints of tree-snakes and the various mottled 
shades of the specips which live in sandy places; but 
it is doubtful whether the colours of many kinds, for 
instance of the common English snake or viper, serve 
to conceal them ; and this is still more doubtful with 
the many foreign species which are coloured with ex- 
treme elegance. 
During the breeding-season their anal scent-glands 
are in active function ; 51 and so it is with the same 
glands in lizards, and as we have seen with the sub- 
maxillary glands of crocodiles. As the males of most 
animals search for the females, these odoriferous glands 
probably serve to excite or charm the female, rather 
than to guide her to the spot where the male may be 
found . 5 ' 1 Male snakes, though appearing so sluggish, 
are amorous ; for many have been observed crowding 
round the same female, and even round the dead body 
of a female. They are not known to fight together 
from rivalry. Their intellectual powers are higher than 
might have been anticipated. An excellent observer 
in Ceylon, Mr. E. Layard , 53 saw a Cobra thrust its head 
through a narrow hole and swallow a toad. “With 
50 Dr. A. Gunther, ‘ Reptiles of British India,’ Ray Soc. 1861, p. 
304, 308. 
51 Oweu, ‘Anatomy of Vertebrates,’ vol. i. 18GG, p. 615, 
52 The celebrated botanist Schleideu incidently remarks (‘Uehor 
den Darwinism™: Unsure Zeit,’ I860, s. 269), that Rattle- snakes use 
their rattles as a sexual call, by which the two sexes find each other. 
I do not know whether this suggestion rests on any direct observations- 
These snakes pair in the Zoological Gardens, hut the keepers have 
never observed that they use their mttles at tin's season more than at 
any other. 
53 “ Rumbles in Ceylon,” 1 Annals and Mag. of Nat. Hist.’ 2nd series, 
vol. ix. 1852, p. 333. 
