OO AKOMODONTIA. 



range. The type of Theriognathus ; figured by Owen in 

 his ' Catalogue of the Fossils of S. Africa,' pi. lxiii. figs. 1-3. 

 Nearly the whole of the bone has disappeared from the 

 facial region of the cranium, and the mandible has also 

 largely exfoliated. The teeth are not shown, but from a 

 comparison with the next specimen the generic position 

 of the specimen is quite evident. This is especially 

 shown by the great width of the interorbital region and the 

 natural cast of the right orbit, which evidently had a bony 

 roof identical with that of the next specimen. Therio- 

 gnathus was placed by its founder near Udenodon. 



Presented by A. G. Bain, Esq., 1853. 



49414. The anterior portion of the cranium ; from the Beaufort 

 (Fig.) beds on the flanks of the Nieuwveldt range. The type of 

 E. uniseries ; figured by Owen in the ' Quart. Journ. Geol. 

 Soc' vol. xxxv. pi. xxvii. figs. 2-9. This specimen is 

 broken off a short distance behind the root of the temporal 

 arcade. The aperture of the posterior nares is well 

 shown, and is seen to be mesially divided by the vomer, 

 and bounded laterally by deeply incurved bones which 

 appear to be the palatines, although they are termed 

 pterygoids by Owen. If this view be correct, the teeth 

 will be situated on the maxillae. The bone on the outer 

 side of the palatine forming the anterior boundary of the 

 palatal aperture of the temporal seems to be the extremity 

 of the pterygoid, and evidently corresponds to the bone 

 similarly situated in the skull of Bicynodon, No. E. 860 

 (p. 27). Purchased from T. Bain, Esq., 1878. 



Suborder THERIODONTIA. 



This suborder is taken as equivalent to the Pelycosauria of Cope l , 

 but cannot at present be fully defined. Some of the most generalized 

 forms referred by Cope to the Pelycosauria 2 are here classed in the 

 undermentioned group Pariasauria, between which and the Therio- 

 dontia there was probably a more or less complete transition. 



1 See Cope, ' Proc. Amer. Phil. Soc' vol. xvii. pp. 529, 530 (1878) ; and Baur, 

 Journ. Morphol. vol. i. p. 102 (1887). The term Pelycosauria is retained by 

 Baur for this group. 



2 Typified by C'lepsydrops and originally regarded as a suborder of Ehyncho- 

 cephalia ; see ' Proc. Amer. Phil. Soc' vol. xvii. pp. 511 and 529 (1878). 



