PLATE IV. 



COMPARATIVE VIEWS OF NASAL HORN CORES. 



(See p. 32.) 



Plate prepared under the direction of Lull. 



Fig. 1. Type of Monoclonius dawsoni Lambe. No. 1173, Canadian Geological Survey. Modified from Lambe. 



Fig. 2. Type of Monoclonius sphenocerus Cope. No. 3989, American Museum of Natural History. 



Fig. 3. Type of Centrosaurus apertus Lambe. No. 971, Canadian Geological Survey. After Lambe. 



Fig. 4. Type of Ceratops {Monoclonius) recurvicornis Cope. No. 3999, American Museum of Natural History. 



After Cope. 

 Fig. 5. Ceratops sp. referred with a query to Monoclonius dawsoni Lambe. by Lambe. No. 190, Canadian 



Geological Survey. Modified from Lambe. 

 Fig. 6. Type of Triceratops horridus Marsh. No. 1820, Yale Museum. 

 Fig. 7. Type of Triceratops prorsus Marsh. No 1822, Yale Museum. After Marsh. 

 Fig. 8. Triceratops prorsus? Marsh. No. 2100, U. S. National Museum. 

 Fig. 9. Type of Triceratops hrevicornus Hatcher. No. 1834, Yale Museum. 

 Fig. 10. Type of Triceratops calicornis Marsh. No. 4928, U. S. National Museum. 

 Fig. 11. Type of Triceratops obtusus Marsh. No. 4720, U. S. National Museum. 

 Fig. 12. Type of Diceratops hatched Lull. No. 2412, U. S. National Museum. 



The figures are all viewed from the left side and are all one-eighth natural size. 



206 



