XIII 



PHYLUM CHORDATA 



491 



this bone, the tympanic being always small, and never ankylosed 

 to neighbouring bones. The internal carotid artery perforates the 



Icr- fr 



p.maoc 



par 



s.oc 



max 



oc.con 



par.oc 



FIG. 10(53. Skull of Dasyurus (lateral view), al.sph. alisphenoid ; any. angular process of 

 mandible; /V. frontal; jv. jugal ; Icr. lacrymal ; </<",>. maxilla; iias. nasal; oc. cond. occipital 

 condyle ; orb.sph. orbitosphenoid ; par. parietal ; 'par.oc. paroccipital process ; p.r,i..':. pre- 

 maxilla ; s.oc. supra-occipital ; sq. squamosal ; sq'. zygomatic process of squamosal. 



.771GLZE 



esc.oc 



bas.oc 



FIG. 1064. Skull of Rock Wallaby (Pelrogale penicillata) (ventral '-view). Letters as in 

 Fig. 1063, except all. alisphenoid. In addition, bas.oc. basi-occipital ; bas.spk. basi-sphenoi 

 '\oc. ex -occipital ; pal. palatine; pt. pteiygoid ; ty. tympanic. 



basi-sphenoid. The optic foramen is not separate from the 

 sphenoidal fissure. In all except Tarsipes the angle of the 



