REPTILES. 349 



how much surprise I felt at the beauty of the first coral-snake 

 which I saw gliding across a path in Brazil. Snakes colored in 

 this peculiar manner, as Mr. Wallace states on the authority of 

 Dr. Gunther,°= are found nowhere else in the world except in S. 

 America, and here no less than four genera occur. One of these, 

 Blaps, is venomous; a second and widely-distinct genus is doubt- 

 fully venomous, and the two others are quite harmless. The 

 species belonging to these distinct genera inhabit the same dis- 

 tricts, and are so like each other, that no one "but a naturalist 

 "would distinguish the harmless from the poisonous kinds." 

 Hence, as Mr. Wallace believes, the innocuous kinds have prob- 

 ably acquired their colors as a protection, on the principle of imi- 

 tation; for they would naturally be thought dangerous by their 

 enemies. The cause, however, of the bright colors of the venom- 

 ous Elaps remains to be explained, and this may perhaps be sexual 

 selection. 



Snakes produce other sounds besides hissing. The deadly 

 Bchis carinata has on its sides some oblique rows of scales of a pe- 

 culiar structure with serrated edges; and when this snake is ex- 

 cited, these scales are rubbed against each other, which produces 

 "a curious prolonged, almost hissing sound. "°^ With respect to 

 the rattling of the rattle-snake, we have at last some definite in- 

 formation: for Professor Aughey states,"* that on two occasions, 

 being himself unseen, he watched from a little distance, a rattle- 

 snake coiled up with head erect, which continued to rattle at short 

 intervals for half an hour: and at last he saw another snake 

 approach, and when they met they paired. Hence he is satisfied 

 that one of the uses of the rattle is to bring the sexes together. 

 Unfortunately he did not ascertain whether it was the male or 

 the female which remained stationary and called for the other. 

 But it by no means follows from the above fact that the rattle may 

 not be of use to these snakes in other ways, as a warning to ani- 

 mals which would otherwise attack them. Nor can I quite dis- 

 believe the several accounts which have appeared of their thus 

 paralyzing their prey with fear. Some other snakes also make a 

 distinct noise by rapidly vibrating their tails against the surround- 

 ing stalks of plants; and I have myself heard this in the case of a 

 Trigonocephalus in S. America. 



Lacertilia. — The males of some, probably of many kinds of liz- 

 ards fight together from rivalry. Thus the arboreal Anolis crista- 

 tellus of S. America is extremely pugnacious: "During the spring 

 "and early part of the summer, two adult males rarely meet -with- 



«2 •Westminster Review,' July 1st, 1867, p. 32. 

 i» Dr. Anderson, 'Proc. Zoolog. Soc.' 1871, p. 196. 

 * 'The American Naturalist,' 1873, p. 85. 



