(55) 



3. On Two New Tlierocephalians from the Gouph. 



TROCHOSAURUS INTERMEDIUS, g. et sp. nov. 



This new genus and species is founded upon a weathered and 

 crushed skull and lower jaw found on the farm Abraham's Kraal, 

 in the Prince Albert Division, in beds belonging to the Pareiasaurus 

 zone. The parietal region is incomplete and the occipital plate is 

 missing, while the zygomatic arches are very weathered. Fracturing 

 of the skull has displayed the structure of the palate. 



The right premaxilla bears five incisors, of which only the fifth 

 retains the crown. They are subequal in size, and together occupy 

 a space of 48 mm. at the margin of the bone. The 5th, which is 

 slightly smaller than the others, has a diameter of 6'5 mm. at the 

 gums and is 15 mm. long, curving slightly backwards. The incisors 

 were simple, pointed teeth, apparently without serrations or longi- 

 tudinal grooves. There is a diastema of 7 mm. between the fifth 

 incisor and the first canine. There are two canines, both of which 

 were large and functional, the second being slightly larger than the 

 first. In section the teeth were apparently oval. A section across 

 the snout shows a smaller replacing tooth lying internal to the first 

 canine and parallel to it. Close behind the second canine came the 

 small molars, of which there do not seem to have been more than 

 four. 



The nostrils are large and are placed almost terminally. Almost 

 the whole of the lower border is formed by the large septomaxillary, 

 which sends off a turbinal process partially dividing the nares into 

 two portions. Between the septomaxilla and maxilla is the usual 

 outer foramen. 



The nasal is fairly broad and comparatively short. 



The interorbital width is almost twice that of the intertemporal 

 region. The f rentals are large, forming 9 mm. of the upper border 

 of the orbit. 



The limits of the prefrontal and lachrymal are not wholly 

 determinable, but the prefrontal was certainly large. 



There is a distinct though small postfrontal, which forms no part 



