THK OPHIUIA. 



239 



Mx 



The maxillarles give attachment to a long series of re- 

 curved teeth, which are not very xmequal in size. And 

 Pytho7i (like Tortrix, but unlike all other OiMclia) jdos- 

 sesses teeth in the premaxillse. 



The squamosal bones are very long, and adhere to the 

 skull, iipon which they are slightly 

 moveable, only by their anterior 

 ends; and the quadrate bones are 

 borne upon the posterior ends of 

 the squamosals, and are thus, as 

 it were, thrust away from the 

 walls of the skull. The rami of the 

 mandible are loosely connected by 

 an elastic symphysial ligament. 

 Thus, not only can these rami be 

 widely separated from one another, 

 but the squamosal and quadrate 

 bones constitute a kind of jointed 

 lever, the straightening of which 

 permits of the separation of the 

 mandibles from the base of the 

 skull. And all these arrangements, 

 taken together, allow of that im- 

 mense distension of the throat 

 which is requisite for the passage 

 of the large and iindivided prey of 

 the serpent. 



In Tortrix, this mechanism does 

 not exist, the short quadi-ate bone 

 being directly articulated with the 

 skull, while the squamosal, like the 

 postfrontal, is rudimentary. The 

 maxillary bones are also almost fixed to the skull. 



In the Rattlesnakes [Crotalus, Fig. 74), the premaxiUag 

 are very small and toothless. The maxillary bone has 

 no longer the form of an elongated bar, biit is short, 

 subcylindrical, and hollow; its cavity lodges the fossa 

 formed by the integument in front of the eye, which is so 



au 



Fi 



3. — Uiider-view of 



die left half of the skuU 

 and facial bones ot Pi/- 

 thoii. 



