Family Typhlopidae. No ectopterygoids or tabulars. Maxillae vertical, toothed; maxillae and mandibles edentulous. Vestiges of pelvis present.
The Typhlopidae with but a single living genus and about one hundred species are widely distributed in the tropical regions. They are burrowing in habit. A single extinct form (Symoleophis Sauvage) from the Cretaceous of France (Senonian) has been referred here; the single known vertebra is more probably that of a dolichosaur lizard.
Family Boidae (Pythonidae). Ectopterygoid and coronoid present. Maxillae horizontal, reaching premaxillae, with solid teeth, the latter with or without teeth. Tabular long, or short and closely attached to the skull (Illysiidae). Vestiges of hind limbs present.
A family of wide distribution comprising about sixty species, some of them attaining a length of nearly thirty feet. Boas, anacondas, pythons, etc.
Upper Cretaceous. Dinilysia Woodward, Patagonia.
Eocene. Protagaras Cope, Limnophis Marsh, Lestophis Marsh, Boavus Marsh, North America.
Oligocene. Paleopython Rochebrune, Scytalophis Rochebrune, France. Paleryx Owen, England.
Miocene. Heteropython Rochebrune, Scatophis Rochebrune, France. Aphelophis Cope, Ogmophis Cope, Calamagras Cope, North America. Botrophis Mercer, France.
Pliocene. Python Daudin, East India.
Family Paleophidae. Neural spines elongate; vertebrae with an inferior ridge.
Large snakes, probably subaquatic, imperfectly known.
Eocene. Pterosphenus Lucas, Paleophis Owen, North America. Paleophis Owen, Europe.
Family Viperidae. No coronoids. Ectopterygoids present. Maxillae vertically erectile, articulating with prefrontal, excavated (Crotalinae) or not (Viperinae). Poison fangs perforated.
About one hundred living species of these poisonous snakes with erectile fangs are known, widely distributed. Pit vipers (rattlesnakes and copperheads) exclusively in America.[1]
- ↑ [Occur also in Asia and Malaysia.—Ed.]
