90 0. C. Harsh — Omithopoda of the American Jurassic. 



In recognition of the manifest relations of the three groups, 

 Ornitlwpoda as here restricted, Stegosauria, and Ceratoj)sia, 

 sharply defined as suborders, they should be placed together 

 in a single order, which may appropriately be named the 

 Pbedentata. This order should be regarded as of equal rank 

 with the Satwopoda, the Theropoda, and perhaps also the 

 Hallojjoda, as defined by the writer, the whole constituting 

 the subclass known as the Dinosauria. 



Yale University Museum, New Haven, Conn., June 15. 1894. 



EXPLANATION OF PLATES. 



Plate IV. 



Figure 1. — Skull of Camptosaurus medius, Marsh; seen from the left side. 

 Figure 2. — The same skull, with brain-east in position; seen from above. 



Both figures are one-fourth natural size. 

 Figure 3. — TeDth upper tooth of Camptosaurus medius. 



Figure 4. — Fifth lower tooth of same species. Both figures are natural size. 

 a, outer view; b, posterior end view; c. inner view. 



Plate V. 



Figure 1. — Pelvis of Camptosaurus dispar, Marsh; seen from the left. One- 

 twelfth natural size. 

 Figure 2. — Left fore leg of same species. One-twelfth natural size. 

 Figure 3. — Left fore leg of Camptosaurus nanus, Marsh. One-fourth natural size. 

 Figure 4. — Left hind leg of Laosaurus consors, Marsh. One-sixth natural size. 



Plate YI. 



Figure 1. — Lower tooth of Laosaurus consors. Natural size, a, outer view; 



b, posterior end view ; c, inner view. 

 Figure 2. — Posterior sacral vertebras of Camptosaurus dispar ; showing peg and 



notch articulation ; top view. One-fourth natural size. 

 Figure 3. — Dentary bone of Kanosaurus agilis, Marsh; seen from the left. 

 Figure 4. — Ilium of same individual ; left side. Both figures are natural size. 

 Figure 5. — Left femur of Nanosaurus rex, Marsh. One-half natural size, a, 



front view ; b, side view ; c, back view ; d, proximal end ; e, distal end. 



Plate VII. 

 Figure 1. — Left pubis of Laosaurus consors ; outer view. One-fourth natural size. 

 Figure 2. — The same bone of Dryosaurus altus, Marsh. One-eighth natural size. 

 Figure 3. — The same of Camptosaurus dispar. One-twelfth natural size. 

 Figure 4. — The same of Triceraiops prorsus, Marsh. One-twentieth natural size. 

 Figure 5. — The same of Claosaurus annectens, Marsh. One-sixteenth natural size. 

 Figure 6. — The same of Stegosaurus ungulatus, Marsh. One-twelfth natural size. 

 p, prepubis ; p', postpubis. 



