324 SNAKES. 



The three sketches are given merely in illustration of a 

 phenomenon which I cannot attempt to explain or even to 

 comprehend. They were drawn from memory, and are not 

 therefore offered as exact representations, though near 

 enough to serve our purpose. The movement seems to 

 argue some peculiar muscular or nervous connection between 

 each pair. The serpent had not been long dead ; and as no 

 others of this species have since been at the Gardens, I cannot 

 tell whether the same sympathetic movement would be seen 

 in the living viper. I have attentively watched the horns of 

 the other vipers, but never detected the slightest voluntary 

 action in them. Nor do the horns of V. iiasicornis respond to 

 the touch in the same way. A third of the horned vipers 

 is the Cerastes of classic times. Illustrators of books from 

 descriptions only have presented us with this serpent adorned 

 with horns like a young heifer. They are sim.ply scaly 

 appendages like the rest, but when perfect do certainly curve 

 backwards and upwards in a rather bovine fashion. It 

 happened that a Cerastes was brought to the Gardens just 

 after the six-horned viper had died, affording me a happy 

 opportunity of examining it. It was of this viper that Pliny 

 wrote : ' It moves its little horns, often 4 in number, to attract 

 birds, the rest of its body lying concealed.' It is the habit 

 of all those inhabiting sandy deserts thus to hide themselves, 

 probably to escape the scorching, drying sunshine, and with 

 perhaps the nose and upper part of the head exposed for 

 breathing. I have carefully watched several of the horned 

 vipers for a long while together, but have never detected the 

 slightest volitional movement in their horns. A bird might 

 come and peck at them, nevertheless. Another belonging 



