in front is the nasal shield, sometimes single with the 

 nostril piercing it, but generally double, with the nostril be- 

 tween the two. Surrounding the eye, we have the supra- 

 ocular shield above it, the prse-ocular in front and the post- 

 ocular behind it. Sometimes there is a sub-ocular beneath it 

 but not often. These shields are often double or triple. 



Between the nasal and the prae-ocular are generally one 

 or more shields called the loreal. But the loreal is absent in 

 many kinds, e.g , the cobra and the krait. 



Behind the post-oculars are a few more shields called 

 temporals. 



Forming the upper lip of the snake (Fig. 2) are a series 

 of shields called the supra-labials. They vary in number 

 from four or five to about nine. One or more enter the orbit 

 when there is no sub-ocular. In the diagram there are seven 

 supra-labials and Nos. 3 and 4 enter the orbit.* 



Now looking at the under part of the head, i.e., the 

 lower jaw (Fig, 3) ; in front we notice a single shield correspond- 

 ing to the rostral. This is called the mental. From this the 

 infra-labials run back on either side forming the lower lips of 

 the snake. 



Between the two series of infra-labials are two pairs of 

 shields known as the anterior and posterior subHnguals or 

 chin shields respectively. 



Noce that in counting the infra-labials the last shield 

 which touches tbe posterior sublingual is the last infra-labial. 

 In the diagram there are seven infra-labials. 



This completes the normal head shielding and with the 

 help of the diagrams it should not be difficult to understand. 



Now turn the snake over on to its back and look at its 

 belly (^Figs. 4 and 5). Here we shall see shields of a different 

 sort. They are broad, transverse plates extending right across 



* 111 tiie descriplions of suakes which follow the number of supra-labials is 

 giveu nud those which enter the orbit are added m bnickeis, e.y., " Supra-labials 7 

 '.^1 ijt " 



