Fig. 5—Skull of Glauconia macrolepis. (From British Museum Catalogue of Snakes)
Lettering of the bones as in Fig. [3]
The deviation from the normal type is much greater still when we consider the degraded, worm-like members of the families Typhlopidæ (Fig. [4], p. [43]) and Glauconiidæ (Fig. [5]), in which the skull is very compact and the maxillary much reduced. In the former this bone is loosely attached to the lower aspect of the cranium; in the latter it borders the mouth, and is suturally joined to the premaxillary and the prefrontal. In both the tranverse bone and the supratemporal are absent, but the coronoid element is present in the mandible.
Fig. 6—Skull of Tropidonotus natrix. (From British Museum Catalogue of Snakes)