THE ANNALS 



AND 



MAGAZINE OF NATUEAL HISTORY. 



[EIGHTH SERIES.] 



No. 45. SEPTEMBER 1911. 



XL. — The Skull of Diaderaodon, i(fith Notes on those of 

 some other Cynodunts. By D. M. S. Watson, M.Sc, the 

 Victoria University of Manchester. 



Our knowledge of the skull of Cynodonts dates from 1860, 

 when Owen described the type specimen of Galesaurus 

 planiceps ; hut our more detailed information depends almost 

 entirely on the description by the late Prof. H. G. Seeley of 

 the wonderfully perfect skulls of Gomphognathus and Cyno- 

 gnathus, which were developed by Mr. R. Hall of the British 

 Museum under his supervision. More recently Dr. R. 

 Broom has added something to our knowledge by amending 

 some of Seeley^s descriptions and by the description of some 

 new specimens. Quite recently W. K. Gregory, in his 

 excellent w^ork ' The Orders of Mammals/ has published a 

 figure of the under surface of a Cynognathus skull drawn from 

 a plaster cast, with the assistance of figures ])ublishcd by 

 Seeley and Broom ; he has added to this a clear discussion 

 of its structure, and his description may be regarded as a 

 summary of what is actually known. 



Amongst the specimens obtained by Seeley in South 

 Africa, which are now in the British Museum, is a small 

 skull (R. 3587) from Winnaai'sbaken in Cape Colony be- 

 longing to the genus Diademodun. This skull, which is 

 almost completely undistorted, is preserved in a matrix of 

 liver-coloured micaceous shale, passing occasionally into a 

 „ Ann. & Mag. X. IHst. !Scr. 8. Vol viii. 20 



