4 i8 REPTIL1A ORDER II1.SQUAMATA. 



siderably from the former in the conformation of the bony palate of the skull, 



it is most probable that they have a totally distinct origin. Since they 



agree in this respect with the other seven more specialised 



Boa Tribe. families included in the sub-order, it is not improbable that 

 Family Boida&. these snakes are the survivors of the ancestral stock from 

 which all the latter have originated. The jaws, too, are un- 

 like those of the blind-snakes in that both are armed with a complete series of 

 teeth. The vestiges of the hind-limbs usually take the form of a pair of 

 spurs in the neighbourhood of the vent. The other distinctive features of 

 the family are mainly connected with the structure of the skull ; and as the 

 only other snakes with vestiges of limbs are the small Ilysiidce, which are not 

 likely to be confounded with the members of the present family, it will be 

 superfluous to allude further to these peculiarities. The family, which ranges 

 over all the warmer regions of both hemispheres, is divided into the two sub- 

 families of the pythons or rock-snakes (Pythonince), and the boa-constrictors 

 and sand-snakes (Boince). All the species included in the former are re- 

 stricted to the Old World ; but whereas the typical boas are solely American 

 and Malagasy, some other members of the second group are widely distributed 

 in the Eastern Hemisphere. The first sub-family is particularly characterised 

 by the presence of an additional pair of bones the supraorbitals in the 

 roof of the skull, which enter into the composition of the margins of the eye- 

 sockets. The members of the genus Python are all large serpents, having 

 teeth in the premaxillary or front upper jaw-bones, and a double series of 

 shields on the lower surface of the tail, the latter being distinctly prehensile. 

 Still more important is the presence of 'pits in two of the shields on each 

 side of the fore part of the head ; while other distinctive features are to be 

 found in the characters of the teeth, as well as in the vertical slit formed by the 

 pupil of the eye. There are nine different species of pythons recognised by 

 zoologists ; and these range over Africa and the Oriental countries, together 

 with Australia and New Guinea. Fifteen and even twenty feet is by no 

 means an uncommon length for the larger kinds, such as the Indian P. 

 molurus ; and occasionally specimens grow to between twenty and thirty feet. 



A python, after having suffocated its victim by enveloping it in the coils 

 of its body, proceeds to swallow it by seizing it by the head and gradually 

 drawing it> down. Greatly exaggerated notions are prevalent as to the 

 size of the animals which can be swallowed by pythons and boas ; and the 

 stories of whole buffaloes and large deer are obviously unworthy of credence. 

 Indeed, it seems probable that even a full-grown sheep is too large for the 

 capacity of the leave of even the biggest of the tribe ; and a sheep of half 

 the full size would seem to be about the limit. In habits, pythons are chiefly 

 nocturnal, and they are partial to damp forest districts where water is easy 

 of access. In such situations they not unfrequeritly take up their residence 

 in the roofs of houses when made of straw or other vegetable substances; and 

 a well-known account of the discovery of such an unwelcome intruder into 

 his temporary abode is narrated by Mr. Wallace. Perhaps the most 

 peculiar circumstance in the life-history of these serpents is the incuba- 

 tion of the eggs. These, which comprise a large number, are arranged 

 in a pyramidal heap, round which the parent coils her body ; this posture 

 being in some instances maintained for nearly two months. Regarding 

 the appetite of a python (miscalled a boa) formerly in his possession, 

 Captain Hey land writes as follows : "The animal was brought to me early 

 in January, and did not taste food from that time until the July follow. 



