204 DR. B. rKTRONIEVICS ON THE LOWER JAWS OF THE 



when text-fig. 4 is com pared witli text-fig. 5. So that, altiiough the 

 ]iind end of the dentnry in Cynognathns goes farther back on tlie 

 inner tlian on the outer side, it is clear from this comparison that it 

 did not reach tlie squamosal and that the possibility of an incipient 

 comlyle of the dentary in Cynognathits is excluded. 



Text-figure 8. 



arLsfdent ^ 



I 



I QJt.srt 



dent. 



G-ow plwjna tints : avticular surface of the left squamosal. Nat. size. 



art. ; avticnlar. 



art.sf.dent ?; probable articvilav sui'face of dentary. 

 art.srfqii. ; articular surface of left quadrate. 

 dent. ; dentary. 



The inner side of the jaws shows the same bones in both 

 cnses (comp. text-tig. 3 with text-fig. 6). The comparison shows 

 that the splenial goes farther back in Gomphognathus than in 

 Cynognathiis. 



The essential difference above mentioned that exists in respect 

 to the relation of the articular bones and the hind end of tlie 

 dentary to the squamosal between the Gomphognathiis-^VvM of our 

 specimen a,nd the other specimens known under the names of 

 GomphognatliKS and Biademodon (a general survey of which has 

 been given by Watson, 1911, p. 327 seq.) suggests the well- 

 founded supposition that our specimen is generically different 

 from all the other specimens of the same kind, which are all 

 essentially similar in the above point. Beyond that, a comparison 

 between the lower jaw of Gomphognathus kannemeyeri (figured 

 by Seeley (1) 1895, fig. 2, p. 8) and of Diademodon mastacus 

 (fignred by Broom, 1905, fig. 1, pi. x.) shows that they are similar 

 in shape, while the shape of the lower jaw of our sjjecimen 

 (comp. text-fig. 2), especially the shape of its coronoid process, is very 

 different. So that I agree with Watson in his identification of 

 Gomphogaatlms and Diademodon for all the other specimens 



