EXPLANATION OF PLATE i 



Lateral view of the skull of Brachyccratops montaiiensis. Type : Cat. No. 

 7951 U. S. Nat. Mus., }i nat. size, d, dentary ; /, fenestra in frill ; if, infra- 

 orbital foramen; in.p, interparietal; ;', jugal; /, lachrymal; vix, maxillary; n, 

 nasal ; nh, nasal horn cores ; no, anterior narial opening ; 0, orbit ; os, ossicle 

 on top of nasal horn core ; pd, predentary ; pf, prefrontal ; pm.v, premaxillary ; 

 po, postorbital ; po.h, postorbital horn core ; r, rostral ; s, suture separating 

 halves of nasal horn ; sq, squamosal ; so, sutural border on prefrontal for 

 small supraorbital ; .y...?, sutural surfaces for squamosal ; st.f, supratemporal 

 fossa. 



EXPLANATION OF PLATE 2 



Superior view of the skull of Brachyccratops montaiiensis. Type: Cat. No. 

 7951 U. S. Nat. Mus., %. nat. size. /, fenestra in frill; fo, postfrontal fora- 

 men; in.p, interparietal; n, nasal; nh, nasal horn cores; pf, prefrontal; po, 

 postorbital; poh, postorbital horn core; p.tf, postfrontal; s, suture repre- 

 senting halves of the nasal horn core ; so, sutural border for missing supra- 

 orbital bone ; sq, squamosal ; s.tf, supratemporal fossa. 



