16 



DINOCEKATA. 



Frontal Bones. 



The frontal bones in Diiioceras mlrabUe are shorter than the nasals. 



In all of the known skulls of the Binocerata, the median suture uniting the 



two frontals is entirely obliterated. The sutures joining them with the 



nasals in front, and with the maxillaries on the side, is distinct in the type 



FiGl'KE n. — Skull of Timiceras inrjens. Marsh (No. 1041); with brain-cast in position; st'en from above. 

 FirjtiRE 10. — Same view of skull of Dinoceras disians, Marsh (Xo. 1235). 



/ frontal bone; »«. ma.xillary bone; m'. maxillary protuberance ; n. nasal bone; v'. nasal protuberance; 



2>. parietal bone; j''- parietal protuberance; pm. premaxillary bone; s. supraocoipital crest. 

 Both figures are one-eighth natural size. 



of Dinoceras iiiirabilr, as shown in Plates II and IV. In this sjiecimen, 

 there appeared to be indications of a suture uniting the frontals with the 

 parietals, «hicli indicated that the former bones were very short, and tlie 

 latter very long. The fortunate discovery, however, of a revy young- 

 individual of this genus has cleared up this point beyond doubt. 



