48 REPTILES AND BIRDS. 
of the eye is round or vertical. Most of the species of this family 
belong to the fauna of tropical Africa, which also produces a slender 
form (Psammophis elegans), The other species are of a stouter 
habit, frequenting plains, or at all events living on the ground. Of 
the Indian Psammophis condanarus, Dr. Jerdon procured one which 
had killed and was swallowing a small viper (Zchis carinata), this 
being one of the few instances in which a non-venomous Snake has 
been known to overpower a poisonous one.* We have heard the 
Fig. 12.—Viperine Snake. 
same of a’small boa-like Serpent (C/:/abothrus ?) in the West Indies, 
which is said to prey upon the formidable Crotalide. ‘The Psammo- 
dynastes pulverulentus has a wide geographical range over south- 
eastern Asia and its islands. Although innocuous, it has the aspect 
of a venomous species. 
In a kindred African family, the Rachiodontide, the species of 
Dasypetis have the maxillary teeth minute and few in number (four 
to seven); but they have also some remarkable gular teeth, which 
are formed by the elongated inferior spinous processes of the hinder 
* The Black Snake of North America undoubtedly preys upon the formidable 
Rattlesnake.—Eb. 
