Annals of the Transvaal Museum. 
209 
Owen described the lower jaw of Oudenodon brevirostris in 1876 
( 5 , p. 58). He states there that the angular elements converge and 
unite to prolong backward the symphysial part of the lower jaw. In 
the following it will be shown that these are the opercular elements. 
In discussing the lower jaw of the Anornodontia ( 6 , p. 80), 
Broom adds the following to our knowledge of this part: — The oper- 
cular elements form a sort of -axis round which the dentaries are built 
up. That part of the angular, which forms a process directed down- 
wards and backwards, rests with its upper edge on the articular and 
the surangular. The articular forms a considerable part of the inner 
side of the posterior third of the jaw. When the jaw is viewed from 
the outer side the greater part of the articular is hidden by the 
surangular and the angular. Essentially the same is said of the lower 
jaw of Oudenodon. 
Jaekel gives a figure of the lower jaw of a Di cynodon in “ Hie 
Wirbeltiere,” p. 190. Judging by the dental end, this must be an 
outside view of the right ramus. According to the explanation given 
under the figure, an opercular and a complementary are in this way 
visible behind the dentary. As will be seen from the following descrip- 
tion, I cannot agree with this interpretation. 
According to Watson (8, p. 288), the articular is fused with the 
surangular. The outer face of the combined bones is largely covered 
by the angular, which is divided by a notch. The articulating surface 
of the articular and the inner side of the jaw are unknown, but there 
is definite evidence of the presence of an opercular. 
From these abstracts it will be seen that only very little indeed 
has been made known on this subject, and even that “ facts ” recorded 
on one occasion were contradicted on another, and sometimes by the 
same author. Therefore I think to have done sufficient justice fo the 
different authors in the above, and will abstain from further references, 
except where necessary for completeness. 
Literature. 
1 . — Gwen, R “ Report on the Reptilian Fossils of 
South Africa. Part 2. Descrip- 
tion of the Skull of a Large Species 
of Dicynodon (D. tigriceps, Gw.), 
transmitted from South Africa by 
A. G. Bain, Esquire.” Reprint from 
Trans. Geol. Soc. of London, 2nd. 
Ser. Vol. VII, pp. 233-240, Pl. 
XXIX-XXXIL (Read 16th May, 
1855.) 
2 . -^-Huxley, T. H “ On Some Amphibian and Reptilian 
Remains from South Africa and 
Australia. 2. — On a New Species of 
D icy no dm (D. Murrayi) from near 
Colesberg, South Africa ; and on the 
Structure of the Skull in the Dicy- 
nodonts.” Quart. Journ. Geol. Soc. 
London, Vol. 15, pp. 649-658, PI. 
XXII, XXIII; London, 1859, 
