On ( . Marsh — New Cretaceous Dinosai 425 



The Claosauridw. Only a single row of teeth in use. 

 Cervical vertebra opisthocoelian. Limb bones solid. Fore 

 limbs small, and feet ungulate. 



(4) The OrnMomimidcB. Limb bones hollow. Fore limbs 

 \rerj small; hind limbs of avian type. Feet digitigrade, and 

 angnienlate. 



Older Ceratopsia. Herbivorous. 



(5) The Ceratopsidas, highly specialized forms fully defined 



above. 



(6) The Nodosauridm. Heavy dermal armor. Bones solid. 

 Fore limbs large. Feet ungulate. 



X.» Sauropoda are known from the American Cretaceous. 



v Haven, Conn., April 2 2d, 1890. 



EXPLANATION OF PLATES. 



Plate V. 



Figure 1.— Skull and brain-cast of Triceratops flabellatus, Marsh; seen from 

 above ; one-twentieth natural size, 

 c, supra-temporal fossa : d, epijugal bone ; e, epoccipital bone ; /, brain- 

 cast; h, horn-core; h', nasal horn-core; n, nasal bone; p, parietal; 

 r, rostral bone; s, squamosal. 



Figure 2. — Brain-cast of Triceratops serratus, Marsh; side view; one-half 

 natural size. 

 c, cerebral hemispheres; cb, cerebellum; m, medulla; ol, olfactory- 

 lobe; on, optic nerve; p, pituitary body. 



Figure 3. — Anterior part of skull of Triceratops ])r vr sus, Marsh; side view; one- 

 eighth natural size. 



Figure 4. — Front view of same. 



Figure 5. — The same; seen from below. 



hf, nasal horn-core; n, nasal bone; na, narial aperture; pm, pre- 

 maxillary; r, rostral bone. 



