i 9 8 Appendix, 



a brown claw of no great ftrength, whofe end is tipt with 

 black. 



I have heard fome of the common people call this lizard 

 Dhab : This we are to look upon as an inftance of igno- 

 rance in the vulgar, rather than the opinion of a naturalift 

 well informed ; for the Dhab is a fpecies perfectly well 

 known to be different from this, and is frequently met with 

 in the deferts which furround Cairo, 



----- ^SH^j^-assaassassjass** 



CERASTES, or HORNED VIPER. 



THERE is no article of natural hiflory the ancients- hare 

 dwelt on more than that of the viper, whether poets, 

 phyficians, or hiftorians. All have enlarged upon the particu- 

 lar fizes, colours, and qualities, yet the knowledge of their 

 manners is but little extended. Almoft every author that has 

 treated of them, if he hath advanced fome truths which he 

 has left flenderlyeftabiimed by proof or experiment, byway of 



i compenfation 



