626 OPHIDIA CHAP. 



as to appear hollow or perforated. Behind these enlarged 

 poison-fangs the maxilla carries a series of smaller, solid teeth ; 

 hence the term " proteroglyphous," which means that the anterior 

 teeth are grooved, in opposition to " opisthoglyphous." Both 

 series have been developed independently. 



The Proteroglypha are all extremely poisonous, mostly 

 viviparous, and widely distributed over the whole of the 

 Australian, Palaeotropical and Neotropical regions, with the 

 exception of Madagascar and New Zealand ; they extend north- 

 wards into the warmer parts of North America, and they also 

 range over a great portion of the Palaearctic sub-region, being found 

 in North Africa and South -Western Asia. They form two 

 natural sub-families : Elapinae, with cylindrical tails, and Hydro- 

 phinae or Sea-Snakes, with laterally compressed tails. 



Sub-Fam. 1. Elapinae. The tail is cylindrical. The Elapinae 

 comprise nearly 150 species, which have been grouped into a 



FIG. Ifi7. Map showing the distribution of the Elapine Snakes. 



great number of, mostly somewhat imaginary, genera. In 

 Australia they constitute the great majority of Snakes, there 

 being besides the deadly Elapinae only a few Pythons and 

 Typhlopidae, and very few Colubrinae. 



Naja. The pair of large and grooved poison-fangs are 

 separated by an interspace from one to three small, faintly 

 grooved teeth near the posterior end of the maxillaries. The 

 scales are smooth and without pits, and are arranged in fifteen 

 to twenty-five oblique rows on the trunk, although more occur in 

 the region of the neck ; the vertebral row is not enlarged. The 

 head is but slightly distinct from the neck. Each nostril lies 

 between two nasals and the internasal. The sub-caudals form 

 two rows. The pupil is round. The neck-region can be expanded 



