Fauna and Stratigraphy of the Stormberg Series. 



349 



of the foramen magnum. It is a triangular bone with a narrow 

 short shaft passing down to meet the foramen magnum. Its apex 

 lies under the bifurcating ridge of the parietal. The surface is 

 slightly concave. 



The suture between the exoccipital and paroccipital process is not 

 to be seen. The latter is fairly high and fairly thin; its outer cor- 

 ner is bent almost horizontally and rests on the backwardly-directed 

 part of the squamosal. 



The basicranial region differs from that of the Theropodous Dino- 

 saurs as exemplified by Plateosaurus erlenbergensis. 



The basioccipital forms the majority of the rounded condyle, 

 which lies wholly below the foramen magnum and is slightly hol- 



A. 



VIM <f en .ov: 



B. 



E.O. 



B.O 



B.O. 



int. car. 



Fig. 12. Sphenosuchus acutus, Htn. 



A. Side view of basicranium and brain-case. 



B. Ventral view of basicranium. 



lowed out in the middle of its hinder surface by a small notochordal 

 pit. The bone also forms the base of the foramen magnum. Ante- 

 riorly it thins considerably and then thickens again ; seen from the 

 side its lower border is very strongly concave. The basioccipital 

 tubera are strongly projecting and between them the transverse ridge 

 is deeply hollowed out. The tubera are formed wholly of the basi- 

 occipital, in strong contra-distinction to those of Plateosaurus and 

 are thus somewhat reminiscent of the tubera in the Anomodontia. 

 This likeness is further intensified by the fact that the basisphenoid 

 sends back a process on either side to support the anterior wall 

 of each tuber. Between these basisphenoidal processes and anterior 



