PLATE X. 



Enchodus aviicrodus Stewart. 



Figure 1. — urt, articular; den, dentary; op, opercular; sop, suboper- 

 cular; dentary and opercular are inverted. X %. No. .'il. 



Fig. 2. — den, portion of dentary, inner view; pt, pt', pterygoid.s; qn, 

 qii', quadrates; pal, pal', palatines, x %. No. 812. 



Fig. 3. — Nearly complete skull: art, right ai'ticular; art', posterior 

 portion of left articular; c-c, contour of dorsal side of the skull, taken 

 along the line, s-s; c, diagram of occipital condyle, the lower third being 

 the basioccipital, and the upper two-thirds the exoccipitals; ch, cera- 

 tohyal; ch', portion of the ceratohyal attached to the epihyal, which lies 

 under the metapterygoid and is indicated by broken lines; den, right 

 dentary; den', impression of the left dentary in the chalk, showing that 

 the symphysial portion was tuberculated externally; eth, ethmoid: exo, 

 exoccipital; fr, frontal; nis, mesopterygoid; mt, metapterygoid; op, 

 opercular; pal, pal', palatines; pop, pop', preoperculars; pt, pt', ptery- 

 goids; p, parietal; qu, quadrate; s, suspensory pharyngeal; sp, sphe- 

 notic; vt, vertebra. X V2. No. 379. 



