916 DR. R. BROOM ON THE 



The occiput is badly preserved, but is remarkable for the great 

 lateral extension o£ the exoccipital, which passes out behind and 

 below the squamosal. Owing to some degree of crushing it is 

 difficult to be quite sure of the relations of the external end of 

 the exoccipital, but it certainly extends much further out than in 

 any other known Cynodont. 



The palate, so far as preserved, differs considerably from that of 

 the typical Cynodonts. There is a secondary palate of the ordinary 

 type, but the pterygoid appears to have a larger pterygoid process 

 than usual. Behind the pterygoid process there is a fan-like bony 

 expansion which passes backwards and outwards towards the 

 articular region. It looks as if it might be all pterygoid, but 

 owing to the crushed and weathered condition of the specimen it 

 is impossible to be sure. Possibly, as in the typical Cynodonts, it 

 is part of the alisphenoid. 



The structure of the lower jaw cannot be satisfactorily made 

 out. The dentary has a very large coronoid process ; in fact the 

 coronoid process is as large as the horizontal ramus. There also 

 is some evidence of a condylar process. The articulation is 

 apparently, mainly at least, formed by a rounded articular supported 

 by possibly an angular and surangular. There is a well-developed 

 splenial bone. 



The dental formula is i. y, c. ^, m. -. 



Ifelinodon is closely allied to Sesamodoit and pretty cei-tainly 

 belongs to the same family. The teeth are of the same type, but 

 relatively much smaller. The specimen is so imperfect that it is 

 impossible to make much of the skull. I have figured it as 

 preserved (PL XLVI. fig. 3). 



Sesamodon resembles Bauria and differs from the other 

 Cynodonts in the foUowmg characters : — 



1. The nostril is directed more forwards than outwards. 



2. The nasal is not widened posteriorly. 



3. The prefrontal is larger than the lachrymal and prevents 



the lachrymal from meeting the nasal. 



4. The frontal forms part of the orbital margin. 



5. The postorbital arch is feeble: incomplete in Bauria. 



6. The molars show no sign of cusps. 



In the following characters Sesaynodon comes nearer the 

 Mammals than any of the other known Cynodonts : — 



1. An articulation for the lower jaw which permits of some 



degree of antero-posterior movement. 



2. The lower canine lies outside the edge of the maxilla when 



the jaw is closed. 



In addition to the mammalian characteristics peculiar to 

 Sesamodon, it combines piost of those mammalian characters 

 seen in Baii^ria with most of those found in the other higher 

 Cynodonts. 



