38o NATURAL SCIENCE. June. 



Iguanodont Dinosauria. His early descriptions of the Pythono- 

 morpha (as he termed the extinct Mosasaurian reptiles of the Chalk) 

 led to most interesting discussions with Owen, and added greatly to 

 our knowledge of these marine lizards. 



In reference to the Mammalia, one of Cope's most remarkable 

 generalizations was his so-called Tritubercular Theory, explaining 

 the origin of the cusps in the molar teeth. He believed palaeontology 

 proved that even the most complicated molars could be traced 

 back to simple tricuspid or tritubercular teeth. He also extended 

 Kovalevsky's work on the feet of the Ungulata, and proposed the most 

 natural arrangement of this great Order hitherto suggested. He 

 elucidated the evolution of the camels in great detail, from American 

 fossils ; he also defined a great number of genera and species of other 

 extinct ungulates.. His most important contribution to the subject, 

 however, was the detailed description of the nearly complete skeleton 

 of a Lower Eocence quadruped, which he named Phenacodiis, and 

 made the type of a suborder Condylarthra, believed to be ancestral 

 not only to the true Ungulates but also to most other divisions of 

 placental mammals, including man himself. Finally, he defined 

 the primitive suborder of Carnivora, now universally adopted under 

 his name of Creodonta ; and he added much to our knowledge of the 

 whole order, especially of the true cats. 



One great feature of this systematic work, everywhere conspicuous, 

 is the attempt to define every term, whether specific, generic, of 

 family or higher rank, in a concise diagnosis. Before Cope's time, 

 this method had rarely been applied to extinct animals ; even at the 

 present day it does not prevail so widely as it ought to do. Cope, 

 however, made all his definitions as precise as the variously imper- 

 fect materials would allow ; and he naturally waxed wroth in his 

 reviews of some contemporary literature which contained new names 

 with nothing but an artist's drawing to justify their introduction into 

 scientific terminology. 



As to Cope's philosophy, he began to write on the problems of 

 organic evolution so long ago as 1869, and his researches ran curiously 

 parallel with those of his friend, Alpheus Hyatt, who arrived at the 

 same result from a study of the shells of the extinct cephalopod 

 molluscs. He and Hyatt, indeed, founded the Neo-Lamarckian 

 , school which has flourished so vigorously of late in America, and 

 begins to find increasing favour in the Old World. Several of his 

 most suggestive essays were collected in a volume entitled " The 

 Origin of the Fittest," published in 1887 ; and only last year he sum- 

 marized Ins latest views in a smaller treatise, " The Primary Factors 

 of Organic Evolution." A critical and detailed account of the latter 

 work, by Mr. F. A. Bather, was published in Natural Science for 

 January last, so that a long exposition is not required here. 



Cope believed that all organisms, impelled by some inherent 

 growth-force, which he termed " bathmism," varied in certain definite 



