THE MALLEUS OF THE LACERTILIA, ETC. 



583 



Further 



Mammalia. 

 Sauropsida. 

 Amphibia. 

 Pisces 



Mandible. 

 Ditto. 

 Ditto. 

 Ditto. 



Extramandibular portion, of Mec- 

 kel's Cartilage and Interfenestral 

 Chain. 



Suspeusorium. 



Otic Region 

 ofCrauium. 

 Ditto. 

 Ditto. 



ThuSj since the quadrate does not form any part at all of the 

 interfenestral chain of Sauropsida, it cannot enter into the 

 composition of that of Mammalia. 



2nd. That it is not possible to understand (especially on the 

 theory of Gegenbaur, v. KoUiker, and others) how the Mam- 

 malia could have acquired an articulation of the lower jaw 

 different from that of other gnathostomous Vertebrata, and that^ 

 therefore, he is of opinion that the glenoid cavity of Mammalia 

 ought still to be found in the quadrate bone. 



M. Albreeht has in his hands at the present time the skull 

 of a new-born child, in which the squamous portion of the 

 temporal bone is divided into two parts, viz. : 



a. The squamous portion of the temporal bone, properly so 

 called, the homologue, in his opinion, of the squamosal of 

 Sauropsida. 



/3. The zygomatic portion bearing the glenoid cavity, and 

 thus homologous, with the quadratum of the Sauropsida. 



Other cases of the complete separation of the squamosal and 

 the quadrate are mentioned in literature, and are cited by M. 

 Albreeht. In addition this distinguished anatomist states that 

 he has observed traces of a squamoso-quadratic suture in several 



