Prof. 0. C. Marsh — Classification of Dinosaurs. 389 



available for investigation. The extensive collections in the museum 

 of Yale University contain so many of the important type specimens 

 now known from America, that they alone furnish an admirable 

 basis for classification, and it was upon these mainly that I first 

 established the present system, which has since been found to hold 

 equally good for the Dinosaurs discovered elsewhere. In the further 

 study of these reptiles, it was also necessary to examine both the 

 European forms and those from other parts of the world, and I have 

 now studied nearly every known specimen of importance. These 

 investigations have enabled me to make this classification more com- 

 plete, and to bring it down to the present time. 



Many attempts have been made to classify the Dinosaurs, the first 

 being that of Hermann von Meyer, in 1830. The name Dinosauria, 

 proposed for the group by Owen, in 1839, has been generally 

 accepted, although not without opposition. Haackel, Cope, and 

 Huxley followed, the last in 1869 proposing the name Ornithoscelida 

 for the order, and giving an admirable synopsis of what was then 

 known of these strange reptiles and their affinities. Since then, 

 Hulke, Seeley, and Lydekker, G-audry, Dollo, Baur, and many others, 

 have added much to our knowledge of these interesting animals. The 

 remarkable discoveries in North America, however, have changed the 

 whole subject, and in place of fragmentary specimens, many entire 

 skeletons of Dinosaurian reptiles have been brought to light, and thus 

 definite information has replaced uncertainty, and rendered a com- 

 prehensive classification for the first time possible. 



The system of classification I first proposed in 1881 has been very 

 genei'ally approved, but a few modifications have been suggested by 

 others that will doubtless be adopted. This will hardly be the case 

 with several radical changes recently advocated, based mainly upon 

 certain theories of the origin of Dinosaurs. At present these theories 

 are not supported by a sufficient number of facts to entitle them to 

 the serious consideration of those who have made a careful study of 

 these reptiles, especially the wonderful variety of forms recently 

 made known from America. 



Further discoveries may in time solve the problem of the origin of 

 all the reptiles now called Dinosaurs, but the arguments hitherto 

 advanced against their being a natural group are far from conclusive\ 

 The idea that the Dinosauria belong to two or more distinct groups, 

 each of independent origin, can at present claim equal probability 

 only with a similar suggestion recently made in regard to mammals. 

 This subject of the origin of the Dinosaurs and the relation of their 

 divisions to each other will be more fully treated by me elsewhere. 



A classification of any series of extinct animals is of necessity, as 

 I have previously said, merely a temporary convenience, like the 

 bookshelves in a library, for the arrangement of present knowledge. 

 In view of this fact and of the very limited information we now have 

 in regard to so many Dinosaurs known only from fragmentary 

 remains, it will suffice for the present, or until further evidence is 

 forthcoming, to still consider the Dinosauria as a sub-class of the great 

 group of Eeptilia. 



