Otic Region. 



Pterotic. —Cartilage filled along all of its edges of 

 articulation with the other cranial bones; articulates by 

 interdigitation anterodorsally with the sphenotic, dorso- 

 medially with the epiotic, ventromedially with the exoc- 

 cipital, and anteroventrally with the prootic and 

 sphenotic. Placed transversely along the middle of its 

 ventral surface, the pterotic possesses a low ventrally di- 

 rected flange for muscle attachment. Anterior to this 

 ventral flange the pterotic has a slight concavity on its 

 surface for articulation by fibrous tissue with the pos- 

 terior half of the dorsal edge of the hyomandibular. 



Sphenotic. — Cartilage filled at its medial edge; ar- 

 ticulates by interdigitation anterodorsally with the 

 frontal, anteromedially with the pterosphenoid, ventro- 

 medially with the prootic, posteroventrally and postero- 

 dorsally with the pterotic, and posteromedially on its 

 dorsal surface with the epiotic. On its ventral surface the 

 medial edge of the sphenotic articulates with the anterior 

 end of the dorsal edge of the hyomandibular by fibrous 

 tissue. 



Epiotic. —Somewhat expanded laterally; cartilage 

 filled along all of its edges of articulation with the other 

 cranial bones; articulates by interdigitation anteriorly 

 with the frontal, anterolaterally with the sphenotic, 

 laterally with the pterotic, posteriorly with the exoccipi- 

 tal, and medially with the supraoccipital. 



