336 



R. J. Anderson, 



. The parietal touclies the jugal in Hylobates Mlilleri and separates; 

 the frontal from the portion of the sphenoid that lies in the outer 

 wall of the skull. The temporal also touches the jugal in this animal 

 so that the sphenoid is separated from the parietal. The parietal 

 touches the sphenoid in cebus and also the jugal. Callithrix has 

 the same arrangements and the marmosets follow the same rule. In 

 ChrysothriXj however, the parietals articulate with the jugals but are 

 separated from the sphenoids by the forward extension of the temporals. 

 In the Lemur, Tarsius Spectrum, the same arrangement is very nearly 

 accomplished also. 



I may be permitted to mention here the proportion of the diameters 

 in the parietal bones of a chick in early life. In a chick 13 days in- 



Fig. 41. 

 Arab. 



Fig. 42. 

 Esquimaux. 



cubated the frontal measured 13 mm in the antero-posteri-or diameter 

 by 5 mm at the base and the parietal 3 mm along the antero-posterior 

 diameter internally by 5 mm transverse the squamosal 4 mm antero- 

 post by 3 mm side to side. 



The parietal bones are scales set in membrane. 

 In a chick somewhat younger. 



Frontals 11 mm long- pointed at both ends. 

 Parietals 3 mm long by 5 mm broad. 

 In a full time chick. 



Frontal 20 mm antero-posterior and 11 mm at base. 

 Parietal 5 mm antero-posterior and 8 mm broad. 

 Squamous 8 mm from front to back and 5 mm from above down. 



