VIPERTDvB. 



IT 



Internasals about half the length of the praefrontals ; the latter 

 entering the eye, between the prsoocular and the supraocular ; 

 frontal longer than broad, a little shorter than the parietals : 

 supraocular moderate, nearly half the width of the frontal ; a small 

 loreal ; one praeocular, one postocular, and three or more snb- 

 ocnlars, excluding the labials from the eye; temporals 2 + 2; 

 upper labials 7, seventh very large ; three pairs of large chin- 

 shields. Scales in 15 rows, dorsals faintly keeled. Ventrals 164 ; 

 anal entire; subcaudals 51. Pale brown or reddish brown above, 

 with transverse series of dark brown nnd white spots ; lower parts 

 brownish white, spotted with brown. 



Total length 16 inches ; tail 2-5. 



Hob. Tenasserim. 



Family IX. VIPERID.E. 



Facial bones movable ; transpalatine present ; pterygoid ex- 

 tending to mandible ; supratemporal present, attached scale-like to 

 the skull and supporting the quadrate ; maxillary short and thick, 

 movable perpendicularly to the transpalatine, and bearing a pair of 

 large canaliculate fangs. Mandible without coronoid bone, armed 

 with solid teeth. 



Fig. 121. Skull of Trimercsnnis gramiwius. 

 A. Upper view. B. Side view. 



ar. Articular. 

 bo. Basioceipital. 

 ca. Columella auris. 



d. Pentary. 

 eo. Exocciuital. 



/. Frontal. 



m. Maxillary. 

 n. Nasal. 

 p. Parietal. 

 pf. Poiaon-fang. 

 pm. Praemaxillary. 

 prf. Praefr.jnt.al. 



pro. Prootic. 



pt. Pterygoid. 

 ptf. Postf'rontal. 



q. Quadrate. 



st. Supratemporal. 



tp. Transpalatine. 

 2E 



