30 WILLIAM K. GREGORY 
QOuadratum 
: Stapes 
Articulare P 
Complementare 
Dentale Angulare 
Supraangul, 
B Goniale Malleus 
(Proc. ant. mallei) Incus 
Stapes 
Cart. Meckel. 
Cornu hyale 
Dentale hyoid 
Fig. 20 Schematic representation of the relations of lower jaw and ossicula 
auditus in (A) saurian embryos and (B) mammal embryos (Gaupp, Verhandl. 
des VIII. Int. Zool. Kongr. zu Graz, 1910, Fig. 9, p. 231). 
Primordial parts of the mandibular arch white, dermal bones of the Meckelian cartilage gray, stapes 
cross hatched, ‘ventrohyal’ obliquely hatched. In Sauropsida the upper section of the ventrohyal is 
represented by the columella, in the mammals the upper end of the ventrohyal is connected with the 
auditory capsule (Gaupp). 
that the manubrium arises independently or at least begins to 
chondrify peripherally (Gaupp). Gaupp (’09, p. 96; 711, pp. 458- 
459) however, will not admit that the manubrium is the homo- 
logue of the extracolumella; he is undecided whether it repre- 
sents the down turned retroarticular process of the articular or 
