SNAKES OF CEYLON. 



THE IDENTIFICATION OF A SNAKE. 



Assuming a snake to be dead, its identification is in most 

 cases an easy matter. The inquirer, however, must be 

 prepared to handle his specimen and critically examine it. 

 His powers of observation must be directed to various features 

 upon which the classification of snakes is based, most of which 

 concern the scales and shields which cover the various regions 

 of the specimen. The word " shield " is used to denote the 

 large plate-like epidermal divisions one sees on the heads of 

 colubrines and on the underparts of most snakes, " scale " 

 being reserved for the small divisions such as one sees on the 

 upper part of the body and tail. In order to study these 

 properly the student must equip himself with a high-power 

 watchmaker's lens and a pair of fine pointed compasses. The 

 watchmaker's lens is recommended because it permits the 

 use of both hands during the manipulation of the specimen, 

 and it mast be remembered that during use both eyes are kept- 

 open, if the lens is to be easily retained in the eye. The 

 compasses are necessary, because all measurements referred 

 to have been arrived at by their use, and because the relative 

 breadths and lengths of shields without measurement are 

 often very deceptive. The collector should try to secure his 

 specimens without damaging the lepidosis of the head, for he 

 will soon discover how important the shielding of the head 

 is in identification. 



The first thing to do is to lay the specimen on its back 

 and search for the opening of the cloaca, a transverse 

 slit in the posterior part of its length. This demarcates the 

 end of the body and the commencement of the tail. The 

 body and tail should then be measured and noted. The 

 shields on the belly (ventrals) should then be counted and 



§ 6(6)20 



