;o6 THEROMORPHA 



horns measures 9 inches. The teeth are small and resemble 

 those of an Iguana in their shape and finely serrated edges, 

 indicating herbivorous habits, but there are also several rows of 

 smaller teeth on the palate, the configuration of which is not 

 unlike that of Sjjhenodon. The top and sides of the skull, 

 except the interparietal foramen, the orbits, and nostrils, are com- 

 pletely encased by rugose, pitted, dermal bones, most of them 

 with strange, horn-like spikes. In the encasement of the 

 temporal region can be discerned a postfrontal, parietal and squa- 

 mosal, a conically projecting epiotic, a postorbital and supra- 

 temporal, a jugal and a quadrato-jugal, which latter almost 

 completely covers the quadrate bone. The interparietal foramen 

 lies far forwards, almost on a level with the orbits. The nostrils 

 are terminal, surrounded 1)y the short nasals, the maxillaries 

 and the premaxillaries, which latter divide them. 



Order II. THERIODONTIA. 



The cranium is not roofed in, but shows a pair of large 

 supratemporal fossae, bordered below by the zygoma, whicli is 

 formed mainly by the squamoso-jugal bridge, and is shut off from 

 the orbit by the postfrontal joining the bridge. The teeth are 

 differentiated into incisors, canines, and molars (Fig. 51:, C, p. 

 280). The lower canines close in front of the upper. 



Cynognathus, Karroo formation of South Africa. C. eratero- 

 notus has a skull aljout 16 inches long, looking like that of 

 a ferocious Carnivore ; tliere are four incisors, huge canines, 

 and nine molars, the latter with serrated edges and . anterior 

 and posterior cusps. The wide supratemporal fossa is bordered 

 and closed behind by the broad lateral extension of the parietal, 

 which joins a similar extension of the squamosal bone. The 

 latter is very long, extending to the postfrontal and to a 

 bone which, bordering the orbit posteriorly, is either an upward 

 branch of the jugal, or a postorbital bone ; the latter inter- 

 pretation is made proljable by the occurrence of a suture with 

 the jugal in C. platyceps. The jugal bone is very long, begin- 

 ning at the quadrate, running along the squamosal, and forming 

 the lower border of the orbit. 



The number of vertebrae is large, there being as many as 

 tw^enty-nine presacrals, six of which belong to the cervical region. 



