108 Trof. H. G. Seeley — On Oudenodon from the Cape. 



The prognathous type, with a median crest between the temporal 

 ■vacuities, includes the species D. lacerticeps, D. leoniceps, D. pardiceps, 

 and D. feliceps. They are grouped under the name Ehachicepha- 

 LODON. I have no doubt that one-half of Oudenodon with the concave 

 parietal region should be closely associated with the similarly 

 characterized half of Dicynodon, and that the half of Oudenodon 

 "with a parietal ridge should be associated with the Dicynodonts 

 which have the same character. Yet owing to the absence and 

 presence of teeth in the two groups there may be some convenience 

 in keeping the types distinct. In tabular form these species may 

 stand thus : — 



Oudenodon. 

 Aulacocephalus. Rhachiocephalus. 



Baini. magnus. 



raniceps. prognathus. 



megalops. brevirostris. 



? strigiceps. Greyi. 



Dicynodon. 



Aulacephalodon. Rhachicephalodon. 



Baini. lacerticeps. 



tigriceps. leoniceps. 



testudiceps. pardiceps. 



feliceps. 



Almost all these specimens were obtained from the Graaff Eeinet 

 district and the Fort Beaufort district, at the time when Cape 

 Colony was expanding to the east, and Mr. A. G. Bain was engaged 

 in making military roads. The Aidacephalodon tigriceps is from the 

 Gonzia River, Kaffraria ; and Aulacocephalus raniceps from East 

 London. As the strike of the beds is the same from Graaff Reinet 

 to East London, ESE., it is probable that these fossils occur upon 

 a definite geological horizon, above the zone of Fareiasaurus and 

 Tapinocephalus, and below the zone of Ftychognathiis (Lystrosatirus), 

 near the bottom of the Middle Karroo, in what have been termed 

 the Beaufort Beds. 



Many years ago Mr. McKay, of East London, sent to this country 

 a small collection of fossils from the black slaty rocks of the East 

 London district. Professor Huxley in 1868 selected one of these as 

 the type of the genus Pristerodon, described in the Geological 

 Magazine for that year. Vol. V, p. 201, PI. XII. 



The collection also included a small Oudenodon now catalogued in 

 the British Museum (Natural History) under the number R. 1819, 

 which is distinct from all described species and may be referred 

 to as Atdacocephalus pithecops. It is somewhat crushed, and is 

 remarkable for its small size, being only three inches long. It is 

 distinguished by the very large size of its nearly circular orbits, 

 which are placed in the middle length of the head, have a diameter 

 of "iV inch, and approximate closely to each other, so that the frontal 

 interspace between them is narrower than the concave parietal area, 

 which is its hinder prolongation. The species is defined from 

 0. magnus by the concave parietal region ; from that species and 



