An<»no(lont SkuU. 81 



on the snrangular. The articular is a much hirger element than 

 I was formerly inclined to believe. Besides forming the whole of 

 the large articulation, it forms a considei"ible i)art of the inner 

 side of the posterior third of the jaw. When the jaw is viewed 

 from the ottter side the greater part of the articular is hidden by 

 the surangular and angular : and the surangular not only hides 

 l)art of the anterior portion, hut by passing backwards and out- 

 wards against the articidar portion almost completely hides this 

 latter as well. 



In OudenodtDi the sti-uctttre of the lower jaw is essentially 

 similar to that in Li/strosnurus. The dentarj^ is rather large and 

 forms more than half of the jaw. The angular is a hu-ge element 

 which is composed of an anterior process passing forward between 

 the dentary and the splenial, and a posterior greatly expanded 

 portion. This latter sends downwards and inwards a moderate 

 sized plate beloW' the general line of the lower border of the jaw, 

 and which recalls the inflected angle of the lower jaw of some 

 Marsupials. The tipper border of the angtilar passes consideraljly 

 outwards from, the general surface, and a deep fossa lies between 

 this ridge of the angular and an outerward passing ritlge formeil 

 by the suraiigul.r. This fossa apparently corresponds to that 

 described by Seeley (") in the jaw of Endothiodon. The surangu- 

 lar aiul articular agree fairly closely with those bones in Lijstro- 

 fidiinis. The splenials are distinct. They add greatly to the 

 symphysis, but do not press far backwards. 



The lower jaw in the small Endothiodonts seems to be very 

 similar to that in Oudenodon. 



References to Literature. 



(1) T. H. Huxley, "On soiue Aiupbibian aud Reptilian Remains from 

 iSoutL Africa and Australia." Quart. Jouru. Geol. Sue, vol. xv.. lS,ji». 



rl) H. G. Seeley, "On the Anoniodont Reptilia and their Allies." Phil. 

 Trans., 1889, B. 



(3) R. Broom, " On the Structure of the Palate in Dieynodou and its 



Allies." Tr. S. Af. Phil. Soc, 1900. 



(4) H. <T. Seeley, "On the skull of Mochlorhinus platyceps, &o." Ann and 



Mag. Nat. Hist. (7), vol. 1, 18^»8, p. 164. 



(o) E. T. Newton. '"Some New Reptiles from the Elgin Sandstones." Phil. 

 Trans., vol. )S4B (189,3), p 4:J1. 



(G) H. 0. Seeley, "Further Evidence of Endothiodon balliystoma (Owen), 

 &c." Quart. Journ. Geol. Soc, vol. xlviii, p. 47t>. 



