dermohyal 



spiracle. 



postspiracular 



intertemporal 

 nasal 



fossa Bridge 



otic branch of VII 



branchiostegol ray 



A PERLEIDUS (EOTRIASSIC) 



lateral rostral 



porasphenoid 



metapterygoid 

 pterygoid 

 ectopterygoid 

 porasphenoid 



loteroi commissure canol 



spinoccipital 

 '/I foramina 



metotic fissure 



vestibular fontanelle 



hyomondibulo 



medial rostrals 

 fused to premoxillo 



nteropercle 

 B ACENTROPHORUS (UPPER PERMIAN) 



suproongula 



angular 



lateral commissure canal 

 sphenotic 

 orbitosphenoid 



pterotic 



supromoxilla 



porethmoid 



epiotic 

 ntercolore 

 exoccipitol 



vertebrae 



porasphenoid 

 lateral ethmoid 



bosioccipital 

 carotid canol 



C LEPIDOTUS (UPPER LIAS-JURASSIC) 



postspiracular 



hyomandibula articulation area 

 otic branch of Vll 

 orbitosphenoid 



lateral ethmoid 



fissure 



4th efferent artery 

 vestibular fontanelle 

 lateral commissure canal 

 porasphenoid 



D WATSONULUS (EOTRIASSIC) 



116 



Figure 5-13. Comparison of the dermal bones of the head, as seen in lateral view, and the endo- 

 crania of two subholosteans, A ond D, and two holosteons, B and C. 



