ON THE QUADRATE IN THE MAMMALIA. 175 



the edge of the ' mastoid ' bone. But at the point where the 

 malleus is connected with the stapes, there springs at right 

 angles to it, downwards and forwards, a longer process (pro- 

 cessus longus mallei), which descends along the inner side of 

 the quadrate, passing between it and the hinder end of the 

 pterygoid and becomes tendinous in front of the inner 

 edge of the articular cavity of the lower jaw, into which it 

 sinks/' 



Peters gives drawings of these relations. That this work by 

 Peters should escape Dollo is so much the more strange, since 

 Balfour, in his f Comparative Embryology,' vol. ii, p. 483 (foot- 

 note), cites him, and Hoffmann, in his ' Reptilia ' (Bronn's 

 ( Klassen und Ordnungen des Tierreichs '), p. 605, not only 

 gives Peters's contribution verbally, but also copies his figures. 



Moreover, this is not the only work by Peters in which the 

 view that the Sauropsida possess a malleus homologous with 

 that of the Mammalia is upheld. Indeed, in the work quoted 

 by Dollo, 1 Peters speaks very decidedly on this point. 



He found in a young alligator, with a head 13 cm. in length, 

 a cartilaginous thread lying in a membranous sheath, which 

 proceeds from Meckel's cartilage of the lower jaw through the 

 aperture which exists at the hinder inner part of the upper 

 surface of the quadrate. This thread he not only traced to the 

 hinder border of the tympanic membrane, but also convinced 

 himself that it is in connection with the cartilaginous plate, 

 which is bent inwards by its narrow middle part towards the 

 columella, the outer end of which is articulated with it. This 

 cartilaginous plate, Peters insists, is nothing but the malleus, 

 as, indeed, Breschet had interpreted it in birds. 



Peters was able to see these relations still more clearly in an 

 embryo crocodile of 70 mm. in length. The same condition 

 of things was also found in an ostrich embryo. On p. 595 

 Peters expresses himself very decidedly and clearly : " In view 

 of the observed facts the view that the articular portion of the 



1 W. Peters, " Ueber die Gehorknockelchen und deu Meckel'schen Knorpel 

 bei deu Krokodilen," ' Monatsber. d. k. preuss. Akad. d. Wiss.,' Nov., 1868, 

 p. 592. 



