most favourable for the snake to pursue or retreat is the 

 least favourable to his prey or his pursuers. 



In a few genera of venomous snakes, Naga (the cobra) 

 and Ophiophagus (the hamadryad) especially, the cervical 

 ribs are elongated and capable of erection from their usual 

 supine state so much as to stretch the skin of the neck into 

 a broad flat disk. 



Three families of Indian snakes, Tortricidce, Pythonidce, 

 ErycidcB, have rudimentary hind limbs. Each limb consists 

 of a claw or spur protruding from a groove on either side 

 of the anus, and internally of two small bones, which may 

 be called the tibia and the tarsus. These relics of a former 

 stage of development can hardly be of any use for progres- 

 sion ; it has been thought that they were of use as auxiliary 

 sexual organs, and this opinion is strengthened by the fact 

 that in Gongylophis conious one of the Erycidce, I find that 

 the male alone is provided with them.- In five adult females 

 which I dissected there was no trace of them ; the only 

 adult male specimen I have is well-spurred. 



The skull is elongated and of somewhat oval shape, being 

 rounded behind the jaws and tapering at the muzzle. Its 

 broadest part is just behind the eye, where it expands above 

 on either side to form the postfrontal bone the posterior 

 bony ring of the orbit ; the anterior, limit of the orbit is 

 formed by a similar bony process, the prefrontal bone, and 

 it is bounded below by the maxillary and by the palate 

 boiie. This part of the head is nearly entirely occupied by 

 the orbital cavities, which in the median line are only 

 separated by the descending plates of the frontal bones. 



The bones of the ophidian skull, exclusive of the maxillary 

 and mandibular arches, I shall merely mention, leaving 

 the comparative anatomist to study them in the page^ of 

 Owen. 



