THE SKULL. 



The Occiput. 



19 



The occipital region in all the known Dlnoccrnta i.s large, elevated, 

 and snbquadrate in ontline. It varies uiucli in shape and size in the 

 different genera and species, and several of the principal forms are 

 represented below in figures 13-18. 



Fig. 13. Fig. U. Fig. 15. 



Figure 13. — Posterior surface of skull of iJiftocerosmiVa'^Ve, Marsh (No. 10:!!j). 

 Figure 14. — -Posterior surface of skull of Dinoceras latksijs, Marsh (No. 1039), male. 

 Figure 15. — Posterior surface of skull of Dinoceras agresle, Marsh (No. 1221). 

 Figure 16. — Posterior surface of skull of Tiiwcuras affine, Marsh (No. 1574) 

 FiGUKE It. — Posterior surface of skull of Ti :o-jTas in/jens, Marsh (No. 1041). 

 Figure 1 8. — Posterior surface of skull of Tinocerus pugnax, Marsh (No. 1 044 1. 



c. occipital condyle; /. foramen magnum; I. lateral crest; o. occipital crest; ;), post-tympanic process; 



I. crest behind temporal fossa. 



All the figures are one-eighth natural size. 



In Dinoceras mirahile (number 1036), the occiput is remarkaljly 

 rectangular in^ outline, as shown above in figure 13. Its general 

 surface is concave, for thfe attachment of the powerful muscles and 



