366 Annals of the South African Museum. 



behind the 3rd cervical. The odontoid process is not anchylosed to 

 the axis. 



The specimen is chiefly valuable, in addition to being a new genus, 

 from its show^ing clearly the distinctness of the postfrontal and post- 

 orbital bones, from its giving evidence that the 2 upper canines 

 are not merely temporary and replacing teeth but morphologically 

 distinct, from its revealing the structure of the auricular, and for the 

 evidence it gives of the structure of the cervical vertebrae. 



Trochosuchus acutus, g. et sp. nov; 



This new^ genus and species is represented by an imperfect skull, 

 also obtained by the Kev. Mr. Whaits at Eietfontein. The specimen 

 is the preorbital portion of the skull of a small Therocephalian 

 which in general appearance is not unlike xElurosaurus. The incisor 

 region of the upper jaw is shallow and the front part of the dentary 

 very deep. It differs from ^^lurosaurus in having 5 incisors, 2 

 canines, and only 3 or perhaps 4 molars. 



The premaxilla carries 5 pointed incisors which are oval in section 

 with a feeble posterior ridge which is serrated in the only tooth in 

 which it is preserved. They are longer than in ^■Elurosaurus. 

 Together they measure 24 mm. Above the premaxilla is seen the 

 rather large septomaxillary. 



The maxilla is of the usual radiating type. Its anterior border 

 hes above the 4th incisor. About 4 mm. behind the 5th incisor is 

 situated the 1st canine. In size it resembles the incisors, but is 

 flatter and has distinct anterior and posterior edges, both of which 

 are probably serrated — the anterior certainly. The second canine is 

 very much larger and is situated 2 mm. behind the first. In section 

 it is oval, with a slight posterior, but apparently no anterior edge. 

 It measures in antero-posterior length about 7'5 mm. There are 

 2 well-developed functional molars and in front of them the roots 

 of 2 others. These anterior 2 are the much-decayed roots of teeth 

 which had ceased to be functional during the animal's life. The 

 first is very small, but the second is equal in size to the 2 functional 

 teeth. The 4 measure 125 mm. Each is oval in section and has 

 no anterior or posterior edges. 



The pterygoids have a number of rounded teeth. 



The nasals are large, and about as broad in front as behind. 

 They measure 50 mm. in length, and 12 mm. in greatest width. 



The length from the front of the orbit to the front of the snout 

 is 73 mm. 



