VERTEBEATA 75 



Quadrate supported by paroccipital, which 



is deeply embraced by the exoccipital 



and petrosal ; frontal and parietal 



little decurved, brain-case open in 



front ; roots of teeth osseous ; Pythonomorpha. 



Quadrate supported by paroccipital which 



articulates with the brain-case direct- 

 ly ; frontal and parietal decurved to 



sphenoid, closing brain-case in front ; 



teeth rootless ; Serpentes. 



In general the Lacertilia have two pairs of limbs, and 

 the corresponding scapular and pelvic arches, but there are 

 many exceptions. The Pythonomorpha known have 

 two pairs of paddles in which all of the elements are dis- 

 tinguishable, and scapular and pelvic arches. In the Ser- 

 pentes limbs and the supporting arches are wanting, ex- 

 cepting rudiments of the posterior in a few forms. 



The three suborders of Squamata first appear in the 

 Cretacic system. The Lacertilia and Ophidia still exist, 

 but the Pythonomorpha do not survive Mesozoic time. 



The Lacertilia embrace the following superfamilies : 



I. Petrosal not produced anterior to semicircular canal, 

 and not articulating above with the parietal ; olfac- 

 tory lobes not under-arched ; hemipenis mostly 

 calyculate. 

 Digits, including metapodials, in opposing 

 groups of two and three about a cen- 

 trale carpi and tarsi respectively ; 

 tongue papillose, extremity sheathed ; 

 no clavicles ; 2 Rhiptoglossa. 



Digits all directed forwards ; clavicles 

 proximally simple ; interclavicle 

 anchor-shaped ; tongue papillose, not 

 sheathed ; 3 Pachyglossa. 



