THE SKULL. 



13 



lu specimens not fully adult, this suture remains an open fissure, and even 

 in some adults it is not closed, especially in the anterior part. 



The osseous prominences on the extremity of the nasal bones are 

 their most marked feature. These vary much in form and size in the 

 ditferent genera of the group, and appear to be characteristic of the species. 



Fifi. ■;. 





Figure 3. — 'Siisa\s of Dinoceras mirabik, Marsli (No. 1036); type specimen. 

 FlcjURK 4. — Nasals of Z>i«ocerfts rffstow, Marsh (No. IGOI); young male. 

 Figure 5. — '!^asa\s of, Tinocems puyttaj; Marsh (No. 10i4). 

 Figure 6. — Nasals of Tinoceras annectens, Marsh (No. 1043). 

 a. side view; 6. top view; c. frofit view. 



All the figures are one-fifth natural size. 



