ON THE QUADRATE IN THE MAMMALIA. 171 



Gegenbaur, Kolliker, Wiedersheim, therefore, regard the 

 malleus as the articulare, and the incus as the quadrate. 



Huxley, Parker, and Bettany look upon the malleus as the 

 quadrate and the incus as the hyomandibular. 



The incudo-mallear articulare articulation, therefore, is to 

 the former zoologists a quadrato-articulare articulation, and 

 to the latter it is a hyomandibular-quadrate articulation. 



Albrecht espouses neither the one view nor the other, and 

 arrives, by his reasoning, at the result that in all Vertebrates 

 the lower-jaw articulation is the same, viz. a quadrato-articu- 

 lare articulation. He then reviews the relations of the auditory 

 ossicles. In the Sauropsida, Coecilia, and Urodela there is a 

 columella. It commences at the tympanic membrane and ends 

 at the " membrana ovalis " (as Albrecht names the membrane 

 which closes the fenestra ovalis). In the Anura four more or less 

 ossified pieces of cartilage are found in the same position ; these 

 four pieces of cartilage are homologous with the columella. 

 In the Mammalia the malleus touches the tympanic membrane; 

 the stapes reaches the fenestra ovalis. Therefore Albrecht 

 concludes, "the columella is homologous with the row 

 of auditory ossicles in the Mammalia. The columella 

 unquestionably forms the suspensorium of the lower jaw. The 

 malleus of the Mammalia belongs to the extra-mandibular 

 portion of Meckel's cartilage, but this portion is homologous 

 with the symplectico-articular ligament of the Amphibia and 

 Sauropsida, therefore the suspensorium of the lower jaw is the 

 same as in all the Vertebrates. 



If, now, the articulation of the lower jaw in Mammals is 

 homologous with that in the rest of the Vertebrates, in which 

 a quadrato-articular articulation is present, then the quadrate 

 must be looked for in that part of the Mammalian skull with 

 which the lower jaw articulates. This, in the Mammalia, is 

 the squamosal : consequently the quadrate of the Sau- 

 ropsida and Ichthyopsida must be comprised in the 

 squamosal. 



Albrecht, indeed, finds in a newborn child affected with 

 double harelip and double " Wolfsrachen," that this squa- 



