374 WILLIAM K. GREGORY 
reptiles Gadow and Broom (’07) took as primitive the conditions 
revealed in early embryos of the crocodile (fig. 22). Here the 
extracolumella is continued downward as a strand of cartilage. 
(the ‘ceratohyal’ of Parker) which is in turn continuous with the 
Meckelian cartilage behind the articular region. Gadow points 
out the parallel between this so-called ceratohyal and the malleo- 
meckelian connection of embryo mammals. He says: 
The whole string, whether cartilaginous or ligamentous, which con- 
nects the downward extracolumellar process with the articulare, is of 
course,= homologous with the continuation of Meckel’s cartilage into 
the malleus of foetal and young mammals. 
A 
Fig. 22 Lower jaw and auditory ossicles of an embryo Crocodile. After 
Parker (lettering slightly modified). 
The hyoid (ceratohyal Parker) is secondarily fused with the posterior part of the articular region of 
Meckel’s cartilage; the hyoid is connected above with the extracolumella and suprastapedial; the stapes 
(St.) fits into the fenestra ovalis. 
But, apart from the suspicion that conditions in the crocodile 
are highly specialized (in correlation with the peculiar Eustachian 
diverticula, ete.), a comparison of the ‘ceratohyal’ of the croco- 
dile with the hyoid of developing lizards leaves no reason to 
doubt the homology, which is indeed endorsed by Versluys (’03), 
after the most thorough researches. Again, in early stages (figs. 
12, 13) of Sphenodon (Howes and Swinnerton ’01), the ascending 
branch of the hyoid is closely appressed to Meckel’s cartilage 
and has every appearance of being homologous with the ‘cera- 
8 Italics mine. 
