214 



THE SKULL. 



[CHAP. 



plate from the palatine, incloses a large cavity, open only 

 behind, which contains the post-palatine air sinus. The 



FIG. 66. Under surface of the cranium of a young Dolphin (Globicepkalus welas). \. 

 BO basioccipital ; ExO exoccipital ; Per posterior (mastoid) process of periotic ; 

 Ty tympanic ; Sq squamosal ; AS alisphenoid ; OS orbitosphenoid ; ZM zygo- 

 matic process of malar ; Fr supraorbital process of frontal ; Ma body of malar ; 

 Pt pterygoid ; PI palatine ; MX maxilla ; PMx premaxilla ; Vo vomer ; gf 

 glenoid fossa of squamosal ; tg deep groove on squamosal for meatus auditonus 

 externus, leading to tympanic cavity ; cf condylar foramen. 



vomer ( Vo) is of great si?e, extends forwards nearly to the 

 apex of the rostrum, embracing the mesethmoid cartilage, 



