THE SKULL. 51 



crest {c), passes craniad in the middle line across the inter- 

 parietal bone : it varies greatly in extent, reaching in a very old 

 and muscular cat to the cranial border of the parietals, while 

 in kittens it docs not exist. The most prominent i:)ortions of 

 the skull in this region, just craniad of the middle of the parie- 

 tal bones, are known as the parietal tubercles or eminences (d). 

 A faint curved line [e) runs from the cranial end of the sagittal 

 rrest craniolaterad to the base of the zygomatic process of the 

 fi'ontal : it marks the dorsal boundary of the origin of the tem- 

 roral muscle, and may therefore be considered the dorsal 

 '"oundary of the temporal fossa. This fossa extends from its 

 dorsal boundary as far laterad and caudad as the lambdoidal 

 ridge {a), and as far craniad as a line connecting the tip of the 

 zygomatic process of the frontal (/) with the frontal process of 

 the malar (//). The temporal muscle takes origin from its 

 .Turface. 



The middle portion of the dorsal surface is formed by the 

 T'Ontals (.5). I'2ach frontal presents laterally a prominent 

 zygomatic process (/), extending ventrolaterad toward a cor- 

 lesponding (frontal) process {/i) of the malar bone. These two 

 processes mark the boundary between the orbital fossa (craniad) 

 cind the temporal fossa (caudad). Craniad of the zygomatic 

 process of the frontal a sharp margin separates the dorsal sur- 

 {?.ce of the skull from the wall of the orbital fossa: this is the 

 supraorbital arch or margin (/). 



The cranial portion of the dorsal surface is formed by the 

 :'naxillary (8), nasal (7), and premaxillary bones (9). Just 

 rianiad of the nasals, bounded ventrad and craniad by the 

 premaxillaries, appears the large opening of tne nares (7), 

 leading into the nasal cavity. 



The zygomatic arch [g) is formed by the zygomatic process 

 of the temporal {iii) and the malar or zygomatic bone (e). 

 Each presents near its middle a prominent dorsocaudally 

 d'/ected process, the frontal process {h) of the malar bone. The 

 ::ygomatic arch forms the lateral boundary of the temporal and 

 orbital fossae, which are separated by a line connecting the 

 fiontal process of the malar (/-) and the zygomatic process of 

 the frontal (/). 



