92 THE COMMON VIPER. 



All the species have scuta, or undivided plates, 

 under the abdomen ; and broad alternate squamae* 

 or scales, beneath the tail. 



In the investigation of this tribe, it is to be re- 

 marked that the subcaudat scales, although alter- 

 nate, are reckoned by pairs ; so that the number 

 marked by Linnaeus for the respective species al- 

 ways means the number of pairs*. 



THE COMMON VIPER f. 



Vipers are pretty generally dispersed over the 

 old Continent, and are by no means uncommon in 

 our own island, particularly in the dry, stony, and 

 chalky counties. 



They do not often exceed the length of two feet, 

 though they are sometimes found above three. The 

 ground colour of their bodies is a dirty yellow, 

 deeper in the female than in the male. The back 

 is marked throughout with a series of rhomboidal 



o 



black spots joining each other at the points ; and 

 the sides have triangular ones. The belly is entirely 

 black J. — They are chiefly distinguished from the 

 Common Snake by their darker belly ; their head 

 much thicker than the body, and in particular by 

 the tail ; which, though it ends in a point, does 



* Shaw's Gen. Zool. vol. iii. 

 + Synonyms. — Coluber beius. Linn. — Vipere. La Cepede. — Vi- 

 per. Pain, — English Viper, Adder. Ray. — Sbavj's Gen. Zool. 'vol. 3. 

 tab. joi. — Penn. Brit. Zool. vol. 3. tab. 4. 



I Pcnn. Brit. Zool. i. 27. 



