THE 
AMERICAN NATURALIST 
VoL. XXXI. December, 1897. 138 
TRITUBERCULY: A REVIEW DEDICATED TO THE 
LATE PROFESSOR COPE. 
By Henry FAIRFIELD OSBORN, 
COLUMBIA UNIVERSITY. 
The morphology of the crowns of the mammalian teeth has 
sprung up practically as a new branch of study since Edward - 
D. Cope and other paleontologists have demonstrated the 
unity of derivation of all the complex forms from the trituber- 
cular type. The older works and ideas of Cuvier, Owen, Hux- 
ley and others are of comparatively little service now, for they 
treat the teeth of each order of mammals as of so many distinct 
types, whereas they must now be treated as modifications of 
one type. This new odontography of the mammalia may be 
dated from the time when it was recognized that the crowns of 
the teeth of the Unguiculata and Ungulata, in the compre- 
hensive Linnsean sense, are based upon a common type and 
are composed of homologous elements of similar origin, as de- 
veloped by Cope, Osborn, Scott, Schlosser and others. It 
dates also from the new embryology of the teeth as studied by 
Leche, Kükenthal, Taeker, Röse, Woodward and others, with 
‘the revelations as to primitive form, number, and milk succes- 
sion. 
But to fully establish the morphological branch in its new 
era we must first demonstrate the theory of a tritubercular 
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