Dinosauria Ornithopoda. 



17 



In Thecodontosaurus platyodon (Fig. 18, D), the teeth have -wall-case 

 oblique serrations on both borders. The ilium is of the Mega- No. 7. 

 losaurian type. Remains of this genus are met with in the Table-case, 

 Upper Trias, Durdham Down, Clifton, near Bristol, in Glouces- 

 tershire. 



SUB-ORDER 3. Ornithopoda (Bird-footed). 

 This sub-order is taken to include the STEGOSAURIA of Marsh. No a 4 " case > 



The genus Stegosaurus was originally described by Marsh 

 from the Tipper Jurassic of North America, but certain forms 

 from the Oxford and Kimmeridge Clay of England, described 

 under the preoccupied name of Omosaurus, cannot be separated 

 generically from Stegosaurus. They also agree with the Scelido- 

 aauridoe in the general structure of their teeth and in the 

 possession of a dermal armour of scutes and spines, as well as 



FIG. 19. The left pectoral and pelvic girdles and limbs of Stegosaurus ungulatus 

 (Marsh), from the Upper Jurassic of Southern Colorado, North America ( T \ nat. size), 

 s, scapula; c, coracoid ; h, humerus; r, radius; u, ulna,; 1-7, phalangeals; il, 

 ilium; is, ischium ; p, pi, pubis ; /, femur; t, tibia; /I, fibula; a, astragalus; 

 c, calcaneum (after Marsh). 



in their solid limb-bones. The neural arches of the vertebras 

 are very much higher, and in the sacrum each arch is chiefly or 

 entirely supported by a single centrum, instead of by the 

 adjacent portions of two centra as in the Ornithopoda. 

 (1876) 3 



