PLATE IV. 



Eiichodus pefrosus Cope. 



portion of the dentary ; abv, abdominal vertebrae; cl, clavicle; cdr, caudal fin 

 portion of the dentary; abv, abdominal vertebrae; cl, clavicle; cdr, caudal fin 

 rays; ch, ceratohyal; den', left dentai-y; den, right dentary; eth, ethmoid; 

 fr, right frontal; />', portion of left frontal; he, hypercoracoid; Itco, hypo- 

 coracoid; op, opercular; pal, right palatine; pal', left palatine; pt, ptery- 

 goid; pst, post-temporal; pr, pr, pterotics; pmx, premaxillary; pt, cephalic 

 end of pteiygoid attached to left palatine; pc, pectoral rays; pa, para- 

 sphenoid; cs, cross section of the same at the point indicated by the broken 

 line; pop. preopercular; gu, quadrate; qit' right quadrate; r, ribs; scl, 

 dorsal end of supraclavicle; sop, subopercular; sp, sp, sphenotics; vt, 

 vertebrae; x, probably the caudal end of the parasphenoid. x Vs. No. 836. 



