VERTEBEATA 43 



Class III.— BATRACHIA. 



There are three subclasses of Batrachia, as follows : 



Basioccipital, supraoccipital, intercalare, and 

 supratemporal bones present; propodial 

 bones distinct ; Stegocephali. 



Basioccipital, supraoccipital, and supratem- 

 poral bones wanting; propodial bones 

 distinct; no urostyle; Urodela. 



Basioccipital, supraoccipital, intercalare, and 

 supratemporals wanting; frontals and 

 parietals connate; propodial bones con- 

 nate; lumbosacral vertebrfe united into 

 a urostyle; Saliodia. 



Subclass I.— STEGOCEPHALI. 



There are four orders of Stegocephali. 



«, One occipital cotyloid articulation. 



Vertebral bodies represented by basal and 



lateral elements (intercentra and centra) ; Ganocephali. 



aa, Two occipital condyles; 



Vertebras represented by distinct and incom- 

 plete intercentra and centra (pleurocen- 

 tra); atlas segmented ; Rhachitomi. 



Centra and intercentra complete, making 



two vertebral bodies to each neural arch; Embolomeri. 



No centra; intercentra each supporting a 



neural arch; Microsauri. 



