PoiiiniKi Ccille"c, Clurcmoiit, Caliti 



57 



The parietals (6) lie in contact with one another for their 

 entire length. They are smaller than the frontals, however, they 

 form less of the dorsal surface of the skull than their real size 

 would warrant, since at their articulations with the frontals these 

 bones extend down over them. Posteriorally each parietal articu- 

 lates with the occipital, and posterio-laterally with the occipital and 

 the sphenethnoid. 



The occipitals (10) are the most posteriorally placed bones in 

 the skull. The dorsal surface of each is more or less regular, di- 

 verging toward the median line to form a short rather slender 

 process which articulates with the other occipital. Anteriorally 

 the occipital connects with the parietal while posteriorally on the ex- 

 ternal side, it articulates with the squamosal. The ventral surface 

 of the occipital is very irregular and the ai'ticulations with other 

 bones are not continuous. Posteriorally on the external side it 

 diverges to form a short process, which unites with the squamosal 

 and forms the posterior corner of the .skull. On the inner aspect 

 of the ventral surface, adjacent to the squamosal articulation, is a 

 projecting knob-like process with which the ptergoid articulates. 



The most posterior portion of the occipital toward the median line, 

 diverges to form a knob-like condyle which articulates with the 

 first vertebra. Anteriorally the occipital articulates with the par- 

 asphenoid and anterio-laterally diverges to form a projection which 

 articulates with the sphenethnoid. 



The squamosal (9) is a peculiar T-shaped bone, standing in an 

 almost vertical position in the skull. The bar of the T, forms a 

 part of the dorsal surface of the skull and articulates at the anterior 

 end with the frontal bone ; at the posterior end with and up past the 

 point where the stem of the T diverges, it articulates with the occip- 

 ital bone. The stem of the T projects ventrally almost at a right 

 angle, and articulates with the ptergoid and the quadrate. 



