PYTHON 329 



pelago, and Australia. They climb as well as they swim ; most of them prefer the neigh- 

 bourhood of water. This family contains the largest snakes. 



Only one genus is found in British India. 



PYTHON. 



PythoDj sp.j Baud. 



Only the anterior half of the upper side of the head is covered with sym- 

 metrical shields, the hinder with scales ; rostral shield and a part of the 

 upper and lower lahials pitted. Nostrils between two shields unequal in size. 



The two species of Indian Eock-snakes are among the largest of living reptiles. Of 

 snakes, only their African congeners and the American Eunectes murimis can be placed beside 

 them. Their dimensions and their strength, however, have been much exaggerated : speci- 

 mens of 18 to 20 feet in length are very rare, although isolated statements of the occurrence of 

 individuals which measured 30 feet are on record and worthy of credit*. Rock-snakes from 

 15 to 20 feet long have the thickness of a man's thigh, and will easily overpower a small deer, 

 a sheep, or a good-sized dog. But although able to kill these animals, the width of their 

 mouth is not so large that they can swallow one larger than a half-grown sheep. The 

 way in which they seize and kill their prey is the same as that observed in numerous 

 smaller snakes : after having seized the victim, they smother it by tlirowing several coils of 

 the body over and round it. In swallowing they always commence with the head ; and as 

 they live entirely on mammals and birds, the hairs and feathers offer a considerable impedi- 

 ment to the passage down the thi'oat. Tlie process of deglutition is therefore slow, but it 

 would be much slower except for the great quantity of saliva discharged over the body of the 

 victim. During the time of digestion, especially when the prey has been a somewhat large 

 animal, the snake becomes very lazy ; it moves but slowly when disturbed, or defends itself 

 with little vigour when attacked. At any other time the Rock-snakes will fiercely defend 

 themselves when they perceive that no retreat is left to them. Although individuals kept 

 in captivity become tamer, the apparent tameness of specimens brought to Europe is much 

 more a state of torpidity caused by the climate than an actual alteration of their naturally 

 fierce temper. The Rock-snakes must attain to a considerable age. A Python reticulatns 

 lived in the menagerie of the Zoological Society of London for fifteen years ; when brought 

 to England it was about 11 feet long, and in ten years it had attained to a length of 21 feet, 

 after which no further growth could be observed. According to observations made by Bibron 

 on young Rock-snakes born in the Garden of Plants in Paris, this specimen would have been 



* We regret to find in tlie ' Reise der Novara/ ii. p. 2-^7, a passage in which it is stated that the tra- 

 vellers saw in Manilla a living " Boa constrictor," 48 feet long and 7 inches thick. Surely none of the 

 naturalists accompanying the expedition can have seen this passage before it was sent to press. 



