1887.] 



of Animals commonly named Dinosauria. 



171 



and the other limb is directed forward. Neither of these limbs of the 

 pabis appears to form a median symphysis. The ilium is prolonged 

 in front of the acetabulum as a more or less slender process or bar. 

 The vertebrae are solid, and the skeleton is not pneumatic. The 

 basi-cranial structure is distinctive, differing from that of Crocodiles 

 and Lizards. The body and limbs are frequently covered with scutes 

 which may form a complete shield or be reduced so as to be unrecognis- 

 able. The digits vary from three to five. 



Sauriscliia. 



In this order the pubis is directed forward from its symphysis with 

 the ischium, and no posterior limb of the bone is developed. Both 

 pubis and ischium appear to meet by a median symphysis, so that the 

 arrangement and relations of the bones are Lacertilian. The anterior 

 prolongation of the ilium has a vertical ^expansion. The vertebras are 

 more or less pneumatic or cavernous ; and in the dorsal region the 

 neural arch is commonly elevated. The basi-cranial structure is sub- 

 lacertilian. No armour has been found. The digits vary in number 

 from three to five. 



I see no ground for associating these two orders in one group, 

 unless that group includes Birds, Crocodiles, Anomodonts, and Orni- 

 thosaurs ; for differences of pelvic structure have been as persistently 

 inherited as any condition of the vertebrate skeleton. 



The classification may be summarised in the following table : — 



Cope, 1866. 



Huxley, 1870. 



Seeley, 1874. 



Marsh, 1878-84. 



Cope, 1883. 



Seeley, 1887. 



Orders. 

 Orthopoda ... 



Goniopoda .. 

 Syniphopoda 



Families. 



( Scelidosauridse 

 ( Iguauodoniidue 



Megalosaurida; 

 Compsognatlia 



Order. 

 Cetiosauria ... 



Orders. 



Stegosauria ... 

 Ormthopoda ... 

 Sauropoda ... 



j TUeropoda ... 



Orders. 



| Orthopoda 

 Opisthocoela* ... 

 Goniopoda 

 Hallopoda. 



Orders. 

 Ornithischia. 

 j- Saurischia. 



* Sir Richard Owen grouped Cetiosaurus and Streptospondylr.s in an extinct 

 sub-order of Crocodilia named Opisthocoela in 1S59 ; while Megalosaurus and 

 Iguanodon were united to form the Dinosauria in 1841. This is the earliest and 

 most definite reference of these animals to separate ordinal groups. 



