B. No coronoid bone; nasals isolated.

1. Maxillary elongate, not movable vertically.

a. Maxillary half as long as mandible.

Supratemporal half as long as skull, projecting far beyond cranium; mandible much longer than skull

Tropidonotus.

Supratemporal not half as long as skull, projecting far beyond cranium; mandible much longer than skull

Zamenis.

Fig. 8—Skull of Coluber longissimus. (From British Museum Catalogue of Snakes)