CERASTES,. 387 



cially the desert sandy part of it. It abounds in 

 the three Arabias, and in Africa. I never savv^ so 

 many of them as in the Cyrenaicum, where the? 

 Jerboa is frequent in proportion. He is a great 

 lover of heat ; for though the sun was burning hot 

 ^11 day, when we made a fire at night, by digging 

 a hole, and burning wood to charcoal in it, for 

 dressing our victuals, it was seldom we had fewer 

 than half a dozen of these vipers, who burnt them- 

 selves to death by approaching the embers. The 

 general size of the Cerastes, from the extremity of 

 its snout to the end of the tail, is from thirteen to 

 fourteen inches : its head is triangular, very flat, 

 but higher near where it joins the neck than to- 

 wards the nose : the length of its head, from the 

 point of the nose to the joining of the neck, is 

 ten twelfths of an inch, and the breadth nine 

 twelfths : between its horns is three twelfths : the 

 opening of its mouth, or rictus oris, is eight 

 twelfths : its horns in length three twelfths : its 

 large canine teeth something more than three 

 twelfths and a half : its neck, at the joining of 

 the head, four twelfths : the body, where thickest, 

 ten twelfths : its tail, at the joining of the body, 

 two twelfths and a half : the tip of the tail one 

 twelfth : the length of the tail ope inch and three 

 twelfths : the aperture of the eye two twelfths, but 

 this varies, apparently according to the impress 

 sion of light. The Cerastes has sixteen small, im-^ 

 moveable teeth, hollow, crooked, inwards, and of 

 a remarkably fine polish, white in colour, inclin- 

 ing to blueish: near one fourth of the bottom i^ 



