VERTEBRATA: REPTILIA. 543 



teeth behind them. The head is shield-shaped, and not much 

 wider than the body. This group comprises some of the most 

 deadly of all the Serpents, one of the best known being the 

 Hooded Snake or Cobra di Capello (Naja tripudians\ which 

 is commonly found in Hindostan, and is the snake usually 

 carried about by the Indian snake-charmers. It varies from 

 two to six feet in length, and the neck can be extensively 

 dilated, covering the head like a hood. A nearly allied species 

 is the Naja Haje (fig. 299) of Egypt. The genus Hungarus, 

 including the deadly " Kerait" (B. cceruleus] of India, is nearly 

 allied to Naja, but the neck is not dilatable. America has 

 representatives of this family in the beautifully-marked Coral- 

 snakes and Harlequin - snakes (Elaps\ and the Australian 

 region is also not without them (Hoplocfphalus, &c.) 



(3.) The Hydrophidce comprise aquatic Ophidians which 

 have the tail vertically compressed and broadened out. They 

 are found principally in the Indian and Chinese seas, often 

 frequenting the mouths of rivers, though sometimes ranging 

 far from land. They are extremely poisonous, and swim with 

 great ease and rapidity. 



(4.) The Colubrina comprise an immense number of alto- 

 gether innocuous snakes, in which the superior maxillae are 

 provided with solid teeth only, and there are no fangs. An 

 excellent example of this group is the common Ringed Snake 

 (Coluber m Tropidonotus natrix) of Britain, a perfectly harmless 

 animal, which is commonly found in damp situations, and 

 which lives mainly upon frogs. Closely allied to this is the 

 Black Snake (Bascanion constrictor] of North America, which 

 attains a length of from three to five feet, but is perfectly 

 harmless, so far as man is concerned. 



(5.) Tht Pythonina comprise the well-known serpents termed 

 the Boas, Pythons, Anacondas, and Rock-snakes. The mem- 

 bers of this group are the largest of all living snakes, attaining 

 a length of certainly over twenty feet. Their bite is perfectly 

 harmless, but they are nevertheless highly dangerous and de- 

 structive animals, owing to their great size and enormous mus- 

 cular power. They seize their prey and coil themselves round 

 it in numerous folds, by tightening which they gradually reduce 

 their victim to the condition of a shapeless bolus, fit to be 

 swallowed. In this way a good-sized Python or Boa will cer- 

 tainly dispose of an animal as large as a sheep or goat, and 

 it is asserted that even human beings may be thus devoured 

 by large individuals of the family. The Boas and Pythons 

 occur in both the Old and New Worlds, the Pythons, however, 

 all belonging to the Old World, and they are amongst the most 



