Elapinae:

Similar to colubrids. Fangs are permanently erect on the anterior ends of largely immovable maxillae and fit into grooved slots in the buccal floor when the mouth is closed (termed the proteroglyphous condition; McCarthy, 1985). Unlike the venomous colubrids, each fang contains an enclosed passae extending the length of the tooth from an opening at the base for entry of the venom to an opening near the tip. Cranially, they have only a left carotid artery, edentulous premaxillaries, longitudinally oriented, shortened maxillaries, with anterior teeth that are large and tubular, parietal-parasphenoid sutures. The mandible lacks a coronoid bone, and the dentray bears teeth. No cranial infrared receptors occur in pits or surface indentations. Intracostal arteries arise from the dorsal aorta at intervals of several trunk segments. The left lung is greatly reduced or absent; a tracheal lung is commonly present in the marine taxa and absent in terrestrial ones. Left and right oviducts are well developed. Some species with viperine appearance have vertical pupils (Acantophis, "death adders"). Elapids and hydrophiids can be distinguished by their choanal processes: elapids have them (except for Dendroaspis), hydrophiids lack them.