Pom )na C()llfL;e, Clnrcniont, California 59 



has no especial markings or features other than the impressions 

 made by the bones which come in contact with it. On its ventral 

 surface are two long narrow impressions left by the squamo- 

 palatines. 



The sphenethnoids (12) are the bones which serve as walls to 

 hold apart the dorsal and ventral surfaces of the skull. They are 

 rather long bones, about three-fourths as long as the parasphenoid. 

 They articulate posteriorally with the occipitaLs, their dorsal edge 

 articulates with the frontal? and parietals, their ventral edge with 

 the parasphenoid. Anteriorally they bound a portion of the open- 

 ings into the occipital fossae. 



The mandibles of Nofofbakniius forosif>i are each composed of 

 two bones, the dentary and the articulare. 



The dentary (14) is that part of the mandible which bears the 

 teeth. It is a long slender, curved bone, articulating anteriorally 

 with the other dentary, and widening out posteriorally to articulate 

 with the articulare. 



The articulare (15) is that part of the mandible which diverges 

 posteriorally to form a rounded knob which fits into the articular 

 socket of the quadrate. Anteriorally, on the median side it fits 

 down into the dentarv bone. 



