3i6 



SNAKES. 



value for distinction of species and genera.' i For this reason 

 each and all of the head shields are specially named. 



Ophiologists differ slightly in distinguishing them as 

 regards assigning the exact position of some of the shields, 

 which, like all other ophidian features, vary in closely allied 

 species. As, for example, while one naturalist may decide 

 that a certain shield is exactly over the eye, another may 

 consider it somewhat to the right or the left. 



Glinther's classification being the one now generally adopted, 

 I copy the names assigned by him, and the diagrams given in 

 his work. 



Fig. I. Top of the head of a Colubrine snake, r, rostral ; /', anterior frontal j 

 /, posterior frontal ; v, vertical ; s, supraciliary ; o, occipital ; t, temporal. 



Fig. 2. Profile of the same, t, temporal ; /, posterior ocular or orbital ; 

 a, anterior ocular or prceorbital ; /, loreal ; n, nasals ; uu, upper labials ; 

 **, lower labials. 



Fig. 3. Under side of the same. **, lower labials ; cc, chin-shields ; 7/i, 

 mental or median lower labial. 



It will be observed that some of these shields can be seen 

 both in the profile and the others as well ; as, for instance, the 



^ Reptiles of British Ifidia, by Dr. Albert Giinther, F. R. S. 



