(58) 



4. On Some Neiu Anomodonts. 

 (Plate XI.) 



DlCYNODON MUSTONIS, Sp. n. 



This species is founded on an almost perfect small skull and lower 

 jaw collected by me in 1913 at Dunedin, Beaufort West. The only 

 parts lacking are the posterior extension of the right squamosal, the 

 right postorbital arch, and the left articular end of the lower jaw. 

 Most of the matrix has been cleared away, and the sutures between 

 the bones are for the most part beautifully displayed. 



In general shape the specimen approximates most nearly to 

 Diictodon Kolbci, although it is but half the size ; but it is generi- 

 cally distinct in that the small preparietal does not entirely surround 

 the pineal foramen, but forms only its anterior border. The anterior 

 half is roughly of the shape of an equilateral triangle, the posterior 

 half almost square. The skull is flat and of graceful proportions. 

 The antorbital portion is short, the orbits large and directed mostly 

 upwards, lying wholly in the anterior half of the skull. 



The premaxillary is large, the internasal process passing back 

 almost to the frontals. The maxilla is comparatively small, although 

 the caniniform process descends considerably below the level of the 

 beak and zygomatic arch. The nostril is large, and is overhung by a 

 prominent rugose nasal boss. There appears to be a small septo- 

 maxillary at the back of the nostril, which does not, however, form 

 any part of the cheek. 



The anterior frontal region is flat, but posteriorly the region 

 between the postorbital arches and extending between the post- 

 orbitals is markedly concave. The frontals are long, passing back 

 almost to the pineal foramen, each separating the two anterior 

 processes of the parietal. There is a marked supraorbital ridge 

 which passes forward into the prefrontal, the ridge becoming less 

 pronounced towards the lachrymal. 



The postfrontals are large, elongate, triangular bones extending 

 back between the parietals and postorbitals to the level of the pineal 

 foramen. The postorbital arch is comparatively slender, and in its 



