THE CROTALID^. 387 



or the principal American Crotdlidce that are not true 

 rattlesnakes, the ' Bushmaster ' {Lacheszs iniLtiis) stands first. 

 This is undoubtedly the largest venomous serpent known. 

 In length it equals the Hamadryad ; and in thickness, the 

 large African vipers. On looking closely at the illustration 

 of this reptile's tail (p. 176), it will be seen that in addition 

 to the spine which terminates it, there are several rows of fine, 

 elaborated scales, which under the microscope appear almost 

 as curiously pointed as those on the head of Vipera nasicornis. 

 Dumeril thus describes the tail: ^ Ponctuee^ et preccdce de 

 dix 02c doiize rangces d'ccailles epinezises^ iin pen courbees en 

 crochets a la pointe' This is the snake called Crotahts viiiet, 

 or ' dumb rattlesnake,' by Linnaeus, and which is supposed 

 to simulate the sound of the rattle by vibrating this point 

 against the leaves ; but many other snakes do this whether 

 their tail is pointed or not, as we saw in chap. xi. Any 

 small thing, such as a twig rustling among dead leaves, 

 would produce the same sound. The near approach of 

 LacJiesis to Cro talus Jiorridiis of the same habitat is, how- 

 ever, seen in this rudimentary rattle, the agitation of which 

 may similarly be attributed to the timidity of these 'highly 

 nervous and irritable creatures,' to repeat Coues' words ; 

 for deadly as they are, timidity strongly displays itself. 

 Watching the venomous snakes when their food is dropped 

 into their cages, their excessive caution, amounting to 

 cowardice, is remarkable, and this with the rattlesnakes 

 especially. One will fix its eyes on the rat which is running 

 about, and shrink back terrified if it approach too closely. 

 Then if the quadruped is a moment quiet, the snake appears 

 to be considering whether it will be advisable to attack it 



