INTEGUMENT 



19 



snakes the small shield or shields behind the 

 rostral are termed " apical," and those on the upper 

 edge of the snout are termed " canthals." The shield 

 which, in Vipers, separates the rostral from the nasal is 



Fig. 2— Head of Zamenis ventrimaculatus. (From " Fauna of 



British India") 



cs, Chin-shields (anterior) ; cs', chin-shields (posterior) ; /, frontal ; 

 in, internasal ; I, loreal ; la, labial (upper) ; la', labial (lower) ; 

 m, mental ; n, nasal ; p, parietal ; pf, prefrontal ; pro, preocular ; 

 pto, postocular ; v, rostral; sbo, subocular ; so, supraocular; 

 t, temporals (first row) ; t' , temporals (second row) ; v> first 

 ventral. 



called " naso-rostral." Allusion has been made above 

 to the scaly dermal appendages which terminate the 

 snout in certain genera. Some Viperidae are furnished 



