CLASSIFICATION OF THE THERIODONTTA. 



53 



thin films of bone, whose outer surfaces are in contact with 

 another pair of similar slender processes. Even in this region 

 the lower edge of the median bone still lies considerably dorsal of 

 the tooth-bearing margin of the maxilla. 



In the next section, about 1 cm. further back, the median 

 plate is shallower, its dorsal margin being curved downwards. 

 The two pairs of plates which support its upper edge are thicker, 

 but still retain their same relations. 



The next slab has fortunately been split longitudinally and 

 somewhat developed, so that it gives conclusive evidence that 

 the lateral pair of processes described above are part of the 



Text-figure 12. 



5 



Scymnognathus wliaitsi Broom. 



Series of transverse sections at about 1 cm. interval, across the snout of No. 49369. 

 B.M.N.H. 1, anterior section; I.N. B., internarial bar; in 2-5 only the 

 internarial bar is represented ; in 6 the maxillae and palatines are shown ; 

 in 7 only the anterior ends of the palatines and pterygoids. X f. 



palatines. The inner pair pass down to the ventral surface and 

 there form a little boss on the palate, which separates the two 

 deep grooves on the palatines. These grooves are so overhung by 

 the more ventral parts of the palatines that their floor can 

 scarcely be seen in a direct ventral projection No sutmes can 



