76 STKUCTURE OF THE SKULL IN SERPENTS. 



tween the elongated parietals and tlie sphenoid ; in the 

 constant coalescence of the parietals with one another ; in 

 the constant confluence of the orbitosphenoids with the 

 frontals, and in the meeting of the orbitosphenoids below 

 the prosencephalon, upon the npper surface of the pre- 

 sphenoid ; in the presence of distinct postfrontals, and the 

 attachment thereto of the ectopterygoids, whereby they 

 form an anterior point of suspension of the lower jaw, 

 through the medium of the pterygoid and tympanic 

 bones ; lastly, in the connation of the prefrontals and lach- 

 rymals. 



In studying the osteology of the head of the python, 

 as the type of the Ophidian Order, by the aid of the fol- 

 lowing description, the student may compare the disar- 

 ticulated skull, ISTo. 628, with that of the large skeleton, 

 No. 602, in the Museum, Eoyal College of Surgeons : the 

 bones are numbered as here referred to. 



The basioccipital, 1, is subdepressed, broadest ante- 

 riorly, subhexagonal ; smooth and concave at the middle 

 above, with a rough sutural tract on each side, and a 

 hypapophysis below, produced into a recurved point. The 

 hinder facet of the basioccipital is convex, forming the 

 lower half of the occipital condyle, which is supported on 

 a short peduncular prolongation. The basioccipital unites 

 above and laterally with the exoccipitals and alisphe- 

 noids, and in front with the basisphenoid, upon which it 

 rests obliquely, and it supports the medulla oblongata on 

 its upper smooth surface. 



The exoccipitals, 2, 2, are very irregular subtriangular 

 bones ; each is produced backwards into a peduncular 

 process, supporting a moiety of the upper half of the oc- 

 cipital condyle. The outer and fore part of the exoc- 

 cipital expands into the irregular base of the triangle : 



