336 Prof. H. G. Seeley on Euskelesaurus Brownii. 



part, formed bj the articular bone, from the outer and anterior 

 margin, formed by the angular bone, which rises in front in a 

 sharp transverse ridge to define the articulation. Posteriorly 

 the articulation is bounded by an elevated margin of the 



Fig. 6. 



Articular end of the left ramus of the mandible, seen from above. 



Anterior extremity of the 

 right ramu3 of the 

 mandible. 



Symphysial gorface 



External aspect of the 

 same specimen. 



Fragment of maxillary 

 bone. 



Anterior part of left ramus of the mandible, showing broken serrated teeth. 

 Mandible of Euskelesaurus from the Kraai River. -Xr nat. size. 



articular bone, behind which transverse ridge, chiefly deve- 

 loped on the inner side, is a very slight heel. This massive 

 articular bone is 3| inches long and about 3-|- inches wide ; it 

 terminates in front in a cartilaginous surface, which is rounded 

 and was presumably invested in bone which is now broken 

 away. It terminates behind in a somewhat vertical truncated 

 surface. Internally it gives off an obtuse process and exter- 

 nally there appears to be a similar process embedded in the 

 angular bone. On the base the internal process is defined by 

 a longitudinal groove, and there is also a groove in front of 

 it. The ramus of the jaw is prolonged forward from the outer 

 margin of the articulation. It is at first 1§ inch deep, the 

 surface, as preserved, is flat, inclined so as to look upward 

 and outward, slightly convex in length, I'ounded from side to 

 side at first on the upper margin, which is about f inch thick. 

 This margin becomes an angular ridge, dividing the inner 

 from the outer surfaces as it extends forward. The hori- 

 zontal plate, which extends inward below the anterior end of 

 the articular bone, appears to be directed downward, and is 

 given off" below the middle of the depth of the side. It 

 appears to consist of two layers — an upper layer nearly | inch 

 thick, and a thin lower layer ; and these two layers have the 

 aspect of being connected by a horizontal suture. As the 

 superior surface is traced forward a deep groove extends above 



