1 



124 



Bulletin American Musewn of Natural History. [Vol. XXVII, 



Mk. ^ ^ Ty. 



c 



Po.F 



---m a e. 



\ N 



Ang. ^^ ^ 



A 



Fig. 2. Morphology of the lower jaw and ossicula auditus. 



A. Lower jaw of a Permian Therocephallan, Lycosuchus vanderrieti, diagrammatic. After 

 Broom. 



D, dentary; p. an., processus angularis; A)7g, angulare; S. ang., surangulare; Ar., articulare; 

 Qu, quadrate; Sq., squamosal; z. Sq., zygomatic process of squamosal. 



B. Skull and lower jaw of Cynognathus platyccps. Diagrammatic composition from figures 

 by Broom. 



Abbreviations as in A above and in Fig. 1, p. 122. m. a. e. osseous auditory meatus. 



C. Developing lower jaw- and ossicula auditiis of a foetal Macropus. After Bensley. 



D. dentary; Mk, Meckehan cartilage, continuous with M, malleus; /, incus; S, stapes; 

 7')/., annulus tympanicus; p. ohj?., processus angularis. 



