60 MR. D. M. S. WATSON ON THE 



mola subsequently described (text-fig. 18). The parietal region 

 is obviously of the Gorgonopsid type and cannot be very wide, 

 although its width cannot be determined with any pretence to 

 accuracy. 



Arctognathus curvimola (Owen), Cat. Foss. Rept. 1876, p. 71, 

 pi. 68. 



The skull (No. 47339 B.M.N.H.) described by Owen as Lyco- 

 saurus curvimola was found with Dicynodon tigriceps in the 

 Cistecephcdus beds of the Kagaberg, near Bedford, S. Africa. 

 Its palate was developed by Mr. Hall and described by Prof. 

 Seeley, Phil. Trans. B. 185. The skull was then examined by 

 Dr. Broom, who noted that the parietal region seemed to be 

 broad, and made for it the genus Arctognathus. 



The actual preservation of this skull is good ; but before it 

 was buried the left maxilla and ectopterygoid, together with the 

 bit of lower jaw in their vicinity, were separated from the rest 

 of the head by a nearly plane split, moved outwards for about 

 15 mm. and there fixed in the sediment. How this very peculiar 

 result was brought about is very difficult to understand, although 

 tentative suggestions might be made. 



Whilst lying at the surface the nodule containing the skull 

 was exposed to weathering, which has cut down into it so as 

 completely to remove the right squamosal, the parietal region 

 beyond the middle line, and the postorbital bar. 



Fracture has removed the occipital condyle and part of the 

 paroccipital process, but has left the stapes and quadrate with 

 the lower jaw in articulation on the right side. Enough of the 

 occiput is left to make the structure clear. The palate is well 

 exposed and very well preserved, the right ramus of the mandible 

 is perfect and well- exposed. 



On the dorsal surface of the parietal region the suture between 

 the parietals and the pineal foramen are very well shown on a 

 weathered face, which lies a little below the original dorsal 

 surface ; the right side of this region retains its natural surface 

 and shows the structure clearly. 



The skull is short, broad, and deep. The snout is rounded in 

 section and terminates in front in the internarial prem axillary 

 processes, which form the extreme front end of the skull over- 

 hanging the oral margin. 



The very large nostril faces largely outward and is not over- 

 hung by an outstanding corner of the nasal. The septomaxilla 

 is small, and the foramen between it and the maxilla very small. 



The interorbital width is considerable, but the orbits look 

 upward and forward as largely as outward. The frontal does 

 enter into the orbital margin, but only through a short distance 

 The postfrontal is a narrow strip of bone wedged in between the 

 frontal and the postorbital. 



No trace of a preparietal is to be seen on the parts preserved, 



