4i6 REPTILIA— ORDER III.—SQUAMATA. 



seen all safe at closing time, but when tlie house was opened next morning, 

 " only one boa was found in the cage ; the other had disappeared. Though 

 the survivor was only a foot longer than the other snake, there was no reason 

 to doubt that it had completely swallowed its companion. It was so dis- 

 tended that the scales were almost separated, and it was unable either to coil 

 itself or to move. There is every reason to believe that in accomplishing this 

 almost incredible feat the snake acted by mistake, and that it devoured its 

 companion by what deserves to be called an accident. The larger boa was fed 

 with a pigeon before the house was closed for the night. It swallowed the 

 bird, and the other boa was then given a pigeon, which it had begun to 

 swallow when the snakes were left for the night. It is believed that the 

 larger snake then caught hold of the part of the pigeon which projected from 

 the other's mouth, and gradually enveloped not only the bird, but the head 

 of the other snake. Once begun, the swallowing process would go on almost 

 mechanically. As the swallowed snake was only one foot less in length than 

 the swallower, and of nearly equal bulk, weighing about fifty pounds, the 

 gastric juices must have dissolved the portion which first entered the snake's 

 stomach before the remainder was drawn into the jaws. Though still rather 

 lethargic, the surviving boa is not injured by its meal. It coils itself up with- 

 out difficulty, and its scales have the beautiful iridescent bloom peculiar to 

 the skin of snakes when in perfect health." Within about a fortnight the 

 cannibal had completely recovered its usual condition. The majority of 

 snakes swallow their prey while still living, as may be often witnessed when 

 a common English water-snake seizes an unfortunate frog. Vipers and 

 cobras, on the other hand, first kill their prey by the injection of venom. 

 But few meals suffice for a snake, in spite of the circumstance that these rep- 

 tiles digest their food with great rapidity. 



In their general mode of life serpents show much variation, some living in 

 sandy deserts, others haunting swampy localities, while yet others spend a 

 large portion of their time in fresh water. Some, again, are mainly arboreal, 

 and the members of one group are marine, and may be met with swimming 

 in the open sea far away from land. The aquatic snakes — both fresh-water 

 and marine — as well as vipers, give birth to living young ; whereas the others 

 lay soft-shelled eggs. Generally these are left to hatch by themselves, aided 

 sometimes by such heat as may be produced by the decomposition of the 

 heaps of leaves and other vegetable substances in which they are not infre- 

 quently deposited ; but pythons actually brood their eggs. It might be 

 thought that incubation by a cold-blooded creature would not aid develop- 

 ment ; but it is a remarkable fact that at such seasons the temperature of the 

 blood of these snakes is raised slightly above the normal. 



Serpents attain their maximum development, both as regards numbers and 

 size, in the steamy tropical and sub-tropical zones ; and it is here also that 

 the most venomous forms are met with. Even in such localities there is, 

 however, groat variation in tlie relative proportions of noxious and innocuous 

 kinds ; and in the large proportion of the former the Oriental countries bear 

 an evil reputation, as they also do in respect to the abundance of snakes in 

 general. Next to these countries comes Tropical America in point of numbers ; 

 whereas Africa has only about half as many snakes as inhabit the Indian and 

 Malayan countries. 'The African serpents are, as a whole, unlike those of 

 Madagascar ; while the latter show a considerable resemblance to South 

 American types. The Australian snake-fauna is allied to that of India and 

 the Malayan countries, as is well exemplified by the occurrence in both of 



