THE DINOSAURIA. 
59 
saurs are of the most slender kind, their resemblances to the 
triassic Crocodilia are more important, and suggest such a 
view as a possibility. 
Professor Cope divided the Dinosauria into three groups. 
The first, Symphypoda, comprises Compsognathus from the 
Solenhofen Slate, and Ornithotarsus from the blew Jersey 
Greensand. The second group, Goniopoda, in which the tarsal 
bones embrace the tibia, includes Megalosaurus and Iguanodon. 
While the third group, called Orthopoda, is represented by 
Scelidosaurus, and comprises Dinosaurs in which the proximal 
tarsal bones are separate, and do not embrace the tibia. 
Professor Huxley has disputed the value of this division, and 
believing Compsognathus to be a type outside the limits of the 
Dinosauria, has united the two groups together under the name 
Ornithoscelida. But seeing that the proximal tarsal bones are 
united with the tibia after the manner of birds in some Ornitho- 
saurs, while in other genera , they always remain separate, it 
seems probable that the Dinosauria might naturally include 
Compsognathus. Professor Huxley has subdivided ordinary 
Dinosaurs into three families, distinguished by their teeth and 
other characters. They are named from typical genera Mega- 
losauridae, Scelidosauridse, and Iguanodontidae. But though 
these are the best marked Dinosaurian groups in England, there 
are many Dinosaurs that it would be difficult to place with 
these. Finally, Professor Marsh proposed a new sub-order, 
Sauropoda, for the gigantic Dinosaurs described by himself and 
Professor Cope from Wyoming and Colorado. I may perhaps 
be permitted to state that on very slender evidence I ven- 
tured to predict the existence of this group nearly ten years 
ago. It happened that I was studying Dinosaurs, and arrived 
at views about the skull which led me to examine a bone 
in tlie British Museum, long previously regarded as the tym- 
panic or quadrate bone of Iguanodon. It appeared to be an 
imperfect dorsal vertebra, and as there was another and earlier 
vertebra in the collection of a like character, I named the form 
Ornithopsis Hulkii, in honour of Mr. Hulke. The genus was 
named Ornithopsis on account of a bird-likeness, in nothing 
more remarkable than in the way in which the bodies of the 
vertebrae were excavated, as in Birds and Pterodactyles for 
the reception of an air-cell prolonged from the lung. Professor 
Cope has shown by his admirable descriptions that this is the 
most remarkable character of the great Colorado Dinosaurs, 
such as Camarasaurus, which differs from Ornithopsis in minor 
generic characters. The type is truly Dinosaurian, and there- 
fore profoundly interesting as showing that animals which put 
on so many avian characters in their bones, acquired lungs 
only comparable in complexity and plan to those of Ptero- 
