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V. — On the Presetice of a 'pair of Distinct Prevomers in Titanosuchus. 

 —By E. Bboom, M.D., B.Sc, C.M.Z.S. 



Mr. a. W. Eogers and Mr. E. H. L. Schwarz, of the Geological 

 Commission, recently obtained in the Gouph, near Van der Byl's 

 Kraal, the anterior part of the skull of a species of Titanosuchus — 

 most probably the type species T. ferox Owen.* It is in a sandstone 

 matrix, and the bones are not in a good condition for developing. 

 Portions of the 10 upper incisors are shown, but in no case is the 

 complete crown present. The greater part of the right canine is 

 seen, but only the impression of the left. The premaxillary bones, 

 though somewhat chipped on the surface, are fairly complete. A 

 distinct suture exists between the two, and each forms half of the 

 well-developed internasal process. The anterior nares, though imper- 

 fectly preserved, are seen to be long and narrow. The whole snout, 

 so far as preserved, is much flatter than is the case of any other 

 known Theriodont except Tapmocephalus, if the latter should prove 

 to be such. 



The most interesting part of the specimen is the fractured surface, 

 showing an oblique section across the anterior part of the palate. 

 There is here seen no evidence of a secondary palate, but in place of 

 it are two very large prevomers. The anterior palatal region is thus 

 seen to be essentially similar to that in Tapinoccphalus. As there 

 are openings of considerable width between the maxillary bones and 

 the prevomers, it is not improbable that the internal nares are here, 

 and that no secondary palate was foi^med even further back than the 

 part shown. 



The presence of the pair of large prevomers in Titanosuchus shows 

 that we have here an important link in the evolution of a most 

 interesting region of the mammalian skull. Until comparatively 

 recently it has been the universally accepted opinion among com- 

 parative anatomists, that the pair of bones found in the anterior 



* The specimen was lying in the river that runs through Knoflock's Fontein, but 

 there is a doubt as to whether it originally came from the rocks on that farm or 

 from Klipbanks Fontein under the Nieuweveld escarpment. 



