Prof. O. C. Marsh on the Dinosauna. 83 



Suborder Cceluria (Hollow-tail). 



(5,) Yi\m\\j Coelurid(e. Bones of skeleton pneumatic or 

 hollow. Anterior cervical vertebrae opisthocoelian, remainder 

 biconcave. Metatarsals very long and slender. 



Genus Coelurus. 



Suborder Cojipsognatha. 



(6.) Family Compsognatlddce. Anterior vertebra3 opistho- 

 coeliau. Three functional digits in manus and pes. Iscliia 

 with long symphysis on median line. Only known specimen 

 European. 



Genus CoinpsognatJius. 



DINOSAURIA ? 

 (5.) Order Hallopoda (Leaping-foot). Carnivorous? 



Feet digitigrade, unguiculate ; three digits in pes ; meta- 

 tarsals greatly elongated ; calcaneum much produced back- 

 ward. Fore limbs very small. Vertebras and limb-bones 

 hollow. Vertebrae biconcave. 



Family Hallopodidce. 



Genus Hallopus. 



The five orders defined above, which I had previously 

 established for the reception of the American Jurassic Dino- 

 saurs, appear to be all natural groups, well marked in general 

 from each other. The European Dinosaurs from deposits of 

 corresponding age fall readily into the same divisions, and, 

 in some cases, admirably supplement the series indicated by 

 the American forms. The more important remains from 

 other formations in this country and in Europe, so far as their 

 characters have been made out, may likewise be referred with 

 tolerable certainty to the same orders. 



The three orders of herbivorous Dinosaurs, although widely 

 different in their typical forms, show, as might be expected, 

 indications of approximation in some of their aberrant genera. 

 The Sauropoda, for example, with Atlantosaurus and Bronto- 

 saurus of gigantic size for their most characteristic members, 

 have in Alorosaiirus a branch leading toward the Stegosauria. 

 The latter order, likewise, although its type genus is in many 

 respects tlie most strongly marked division of the Dinosaurs, 

 has in Sceltdosaurus a form with some features ])ointing 

 strongly towards the Ornitlioj)oda. 



The Carnivorous Dinosauria now best known may all be 

 placed at present in a single order ; and this is widely sepa- 



