592 M. L. DOLLO. 



4th. M. Albrecht's ^ former interpretation, viz. that the jugal 

 when it is not ossified by a particular centre is ossified either 

 by the supra-maxillary or by the quadrato-jugal, appears to me 

 even less capable of defence, for among the living Sauropsida 

 possessing a quadrato-jugal Hatteriais the only one in which 

 this bone is fused to the jugal. In Hatteria we have to deal 

 with an exception. Therefore, why should it be desired to 

 render the condition in the human subject a matter of excep- 

 tion rather than to bring it within the rule ? In other words, 

 it appears to me more rational to assign to Man a separate 

 quadrato-jugal, such as occurs in Birds, Chelonians, and 

 Crocodilia. 



The explanation which follows seems to me a more correct 

 one, because by its application all the objections we have just 

 passed in review disappear. 



Premalar = Jugal. 



Postmalar= Postfrontal. 



Hy pom alar = Quadrato-j ugal. 

 This, if M. Albrecht's quadrate be admitted, gives us the 

 formula : 



Pstfr 



Homo. 



Let us attempt to discover in the Sauropsida an analogous 

 arrangement, in order to better justify our theory. 



If a skull of Hatteria be examined, it is seen that three 

 temporal fossae can be distinguished,^ a latero-temporal, a 

 supra-temporal, and a post-temporal. I have discussed the 

 variations of the latter at length in another memoir,'' and it 



' P. Albrecht, ' Sur la valeur niorphologique de Tarticulation luandibulaire, 

 &c.' Hypomalar = Jugal + Quadrato-jugal. 



2 T. H. Huxley, ' A Manual, &c.,' p. 220. 



^ L. DoUo, " Quaf rienie note sur les Dinosauriens de Bernissart," ' Bull. 

 Mus. Roy. Hist. Nat. Belg.,' t. ii, p. 242. 



