Quadrate not longer than supratemporal; maxillary little longer than quadrate, strongly curved in front of prefrontal
Macroprotodon.
Quadrate longer than supratemporal; maxillary little longer than quadrate, nearly straight in front of prefrontal
Tarbophis.
Fig. 10—Skull of Vipera lebetina. (From British Museum Catalogue of Snakes)
Lettering of the bones as in Fig. [3]
2. Maxillary much abbreviated and erectile; supratemporal not half as long as skull; mandible much longer than skull; basioccipital with a strong process.