868 BR. R. BROOM ON 



lower jaw in position. At first sight the skull might readily be 

 taken for that of a small Oudenodon, but there are two marked 

 differences. There are a number of small maxillary teeth, and 

 the lower jaw ends in front in a pointed beak which fits into a 

 deep depression in the premaxillary exactly as in Endothiodon. 

 There is no tusk. 



The nostril is 8 mm. in length by 7 mm. in depth. The 

 orbit is 12 mm. behind the nostril. The inter-orbital width is 

 probably 14 mm. Close to the outer edge of the maxillary bone 

 are at least two small smooth pointed molars, and other molars 

 are arranged in a row further in. 



The lower jaw is almost typically Eadothiodont. 



The only form nearly related to the present one is that de- 

 scribed by me eight years ago as Prodlcynodon pearstoneiisis. The 

 two agree in the arrangement and structure of the molars, but 

 differ markedly in the proportions of the head. P. pearstonensis 

 has a much broader snout and an enormous premaxillary. It 

 also has the orbit much further back. As neither type is in 

 good condition it is impossible to afiirm with certainty that the 

 two species belong to the same genus, but at present it will be 

 convenient to keep them together. 



When Frodieynodon was first described, and until recently, the 

 presence or absence of a tusk was believed to be a generic dis- 

 tinction. Dicynodon and Oudeiiodonwere believed to be distinct 

 genera. For the last five years the evidence has been steadily 

 accumulating in favour of the tusk being merely a sexual character, 

 and now the evidence seems to be conclusive, Mr. Whaits has 

 collected a large number of the common little Beaufort West 

 Endothiodont Bicelurodon whaitsi, and tusked and tuskless 

 specimens seem to be about equally common, while there are no 

 other characters to separate the specimens, Mr, D, M. S. Watson 

 has succeeded in obtaining two specimens of Oudenodon holorhinus 

 recently described by me from Kuilspoort, a,t the same locality 

 as afforded the type, but one specimen is tusked and the other 

 tuskless. 



This conclusion will necessitate the giving up of the genera 

 Oudenodon and Opisthoctenodon and placing the species of these 

 old genera under Dicynodon and Pristerodon, Fortunately very 

 little confusion will result, as I have for years assumed the 

 possibility of the tusk being merely sexual, 



Dicynodon laticeps, sp, n. (PI, XCII. figs, 12, 13,) 

 This new species of Dicynodon is founded on a beautiful skull 

 obtained by Mr. J. H. NVhaits on the Nieuwveld. With the 

 exception of the lower jaw being missing and the tips of the 

 maxillaries with most of the tusks being broken off, the skull may 

 be regarded as perfect. It belongs to the very unusual broad- 

 headed variety of which only a few specimens are known. When 

 viewed from above the resemblance is so close to Dicynodon 

 tifffieeps Owen as to suggest that it might be a young specimen, 



