IV exits about here 

 frontal 



prefrontal^ 

 nasal 



orbitosphenoid 



parietal 



squamosal 



premaxilla 



VII 



frontal prootic ; y,„ parietal 



columella (stapes) \ ;" '," JI ^J-La-^^ cartilage 



' exoccipifal ,./ \r' I , i i I h /l\. . tz^ ■ -^ i 



IX-X-XI ' * '^ ^./^.•^.•^ \^ 



dentary 



IX-X-XI 



hypohyal / / ""^—J. — / ^angular 



pterygoid quadrate ceratohyal 



premaxilla 



suprocngular -^ palatine artery 



' ■ ., L I / \ ~ ^5k occipital condyli 



orbitospheno.d ^„^„,y ^„„^| \__ _ ^ ^ ._, 



parasphenoid 



supraangular 

 .articular 



prefrontal 



vascular grooveV j prootic 

 IMHV, 



quadrate 



pterygoid 



palatine nerve 

 and blood vessel 



pterygoid 



parasphenoid 



columella (stapes) 

 IX-X-XI 

 exoccipital 



Figure 4-17 Skull and mandible of Cryptobranchus. A, loterol view of head skeleton- B dorso 

 view of skull; C, ventral view of skull; D, medial view of rigfit halt of cranium; E, medial view o 



mandible 



orsal 

 f 



basihyal 



hypohyal 



copula 



hypobranchial I 

 ceratohyal 



ceratobranchio 

 ceratobronchial IV 



ceratobranchial I 



copula (dashed lines) 



hypobranchial IV 



CRYPTOBRANCHUS B NECTURUS C RANA 



Figure 4-18. Hyoid apparatuses of Crypfobranchus, Necturus, and Rana as seen from below. 



OTHER TETRAPODS • 81 



