Chap. IX.} 



SKULL OF OPHIDIA. 



337 



Pmx 



PL 



In the Amphibia the mouth is wide, and in 

 some Anura the symphysis of the mandibles is strong, 

 for it has to serve as the 

 point of attachment of the 

 tongue (see page 154) ; in 

 some TJrodela, as in some 

 Reptiles and Birds, the 

 sclerotic cartilage undergoes 

 ossification, but presents only 

 an advance on what is seen 

 in the Teleostei. 



Owing to our better 

 knowledge of the habits of 

 the higher Vertebrates, we 

 are more easily able to 

 associate the arrangements 

 of parts of their skulls with 

 the habits of their possessors. * 

 Nowhere do we find a better 

 series of mechanical arrange- 

 ments than among the 

 Optiidia; in the python 

 and those that swallow, 

 without poisoning, their 

 prey, the skull is wide be- 

 hind, and the quadrates are 

 at a considerable distance 

 from one another (Fig. 141 ; 

 QM). In other words, the 

 lower jaw is wide at its 

 point of attachment, and, 



as we have learnt already (page 96), the quadrate 

 is movable upon the squamosal (sq), so that the 

 width of the mouth behind can be very considerably 

 increased. 



Anteriorly, there is a corresponding arrange- 

 ment, inasmuch as the lower jaws are not firmly 

 w 16 



Fig. 141. Lower Surface of 

 Skull of Python. 



praz, Premaxillae ; MX, maxillse ; 

 vo, vomer; IT, transverse 

 bone ; pi, palatine ; Ft, ptery- 

 goid; Q, quadrate; sq, sciua- 

 niosal; BS, basisphenoid; 

 BO, basioccipital. (After 

 Huxley.) 



