PF.NTACFRATOPS STERN IU'.R< ill 



109 



tops brevicortms] the fontanel les arc much more elongate than in Triceratops prorsus (cf. PL 

 XXXV) j both the rostrum and the frill are more elongate than in that species. In its dun 

 proportions PenUKermtops sterniergii resembles Triceratops serratus more closely (cf. PI. XXVII) 

 although it differs widely from this species in the three generic characters above noted, namely, the 

 fontanel les, the jugal horns, and the postorbital horns. 



A.M.N. H. 6325 



Fig. 39. — Left lateral view of skull of Pentaceratop sterttbergii, holotvpe, 1/14 natural size, e, epoccipitals; ej, cpi- 



jugal; /, prefrontal; h, supraorbital horn; if, preorbital fossa; it], infratemporal fossa; /', jugal; /, lacrymal; mi, muscle 



impression; m.\; maxillary; >/, nasal; nar, narial opening; tlh, nasal horn; o, orbit; /■, parietal; />/, parietal fenestra; 

 fmx, prcmaxillarv; po, postfrontal; q, quadrate; r, rostral; sq, squamosal. 



"Considering the division of the Ceratopsia into two phyla {of. tit., p. 161), Pentaceratops seems 

 to represent rather the Torosaurus phylum than the Triceratops phylum. It may be an offshoot 

 intermediate in geologic time between the Ceratopsia of the Judith River and Belly River formations 

 and the Torosaurus of the Lance of Converse County, Wyoming. 



"Comparing this animal with the ceratopsians described since the appearance of the Hatcher- 

 Lull Monograph of 1907 we make the following observations: 



"Belly River Formation 



Styracosaurus Lambe, 1913, type S. albertensis 



Protorosaurus (C ' hasmosaurus) Lambe, 1914, type Monoclonius belli Lambe 



"Edmonton Formation 



Anchiceralops Brown, 1914, type A. or nut us 

 Leptoceratops Brown, 1914, type L. gracilis 



"Two Medicine Formation 



Brachyceratops Gilmore, 1914, type B. montanensis 



"Belly River Formation 



Eoceratops Lambe, 1915, type E. canadensis 



