Xll LIFE AND WOEKS OF COPE. 



siz for all forms having enamel-covered scales, and as ap- 

 plied by him, covered a very heterogeneous combination of 

 fishes totally unrelated to each other. Johannes Miiller 

 later retained this name for fishes which were separated 

 from other living forms by a chiasma of the optic nerves, a 

 multi-valvular and muscular conus arteriosus, and an in- 

 testinal spiral valve. In this shape the group, Ganoidei, 

 was long accepted as a subclass or order, but in 1866, 

 Owen broke away from the historic regard for external 

 characters, by uniting the Ganoids and Teleosts into the 

 Teleostomi.* 



Before the American Philosophical Society, in 1870, 

 and the American Association for the Advancement of 

 Science in 1871, Cope maintained that the primary divi- 

 sions of the Teleostomi are indicated by their fin structure, 

 enunciating a principle which now forms the accepted basis 

 of subordinal classification. Fin structure as a taxonomic 

 motive became uppermost in his mind among all the possi- 

 ble keys to the classification of the fishes. It undoubtedly 

 served to direct his attention later to the foot structure of 

 land vertebrates, especially of the great Dinosaurs in 1867 

 and the hoofed mammals in 1880, as of diagnostic value. 



" The evolution of the fins, indeed, and especially of the paired 

 fins, is shown by Cope to be the most satisfactory and philosophical 

 clue to the arrangement of all the minor groups of fishes. Just as 

 the various modifications of the pentadactyl limb in the Ungulate 

 Mammals — the vertebrates which eventually become most com- 

 pletely adapted for progression on land — afford the principal means 

 of determining the natural subdivision of that order ; so among the 

 greater groups of fishes — the vertebrates that become specially 

 adapted for progression in water — the successive modifications of the 

 primitive fin-folds form the most obvious clue to the phases through 

 which the various types have passed in the course of their spec- 

 ialzation." (A. Smith Woodward, Catalogue of Fossil Fishes, Pt. 

 11- P- ^■) 



* Fishes having the mouth surrounded hy specialized membrane bones as in the 

 Teleosts. 



