RELATIVE SIZE OF ALLIED SOUTH AFRICAN REPTILES 



Dicynodon whaitsi Broom and Diictodon galeops Broom. The skull of one of the largest forms of 

 Dicynodon and of one of the smallest allied forms. This specimen of Dicynodon whaitsi is a female in 

 which the tusk does not project but it is present in the specimen deeply embedded in the bone 



Formerly all those specimens of dicynodont reptiles in which there was no manifest tusk were 

 placed in the genus Oudenodon. Oudenodon was also placed by Owen in a distinct family. For years the 

 question was debated by all workers on South African reptiles whether Oudenodon might not be tne 

 female of Dicynodon and all have concluded that the evidence seemed rather to favor their being dis- 

 tinct forms No known specimen of Oudenodon sufficiently resembled any known specimen of 

 Dicynodon to be manifestly the female of that species. Within recent years however it has become 

 quite certain that Oudenodon is the female of the tusked Dicynodon. In at least three species of Dicy- 

 nodon we have a manifest series of tusked and tuskless specimens and the same also occurs in other 

 closely allied genera. In some species there is a rudimentary tusk, in others apparently no trace ot 

 tusk, while just possibly in some of the larger forms, such as Dicynodon (Kannemeyena), most proba- 

 bly the female is also tusked . • 



Exactly what the function of the tusk may have been is unknown. Many suggestions have been 

 made which are manifestly incorrect. Pretty certainly the tusks have nothing to <^with the pro- 

 curing of food as the females in which they are absent doubtless got on as satisfactory Probably 

 they were in Dicynodon at least, secondary sexual characters like the spur in the duck-billed platypus 



343 



