1893.] The Ancylopoda, Chalicotherium and Artionyz. 123 
Ungulate affinities of chalicotherium. M. Filhol’s view is 
that this genus belongs to a group which bridges the gap 
between the Edentates and Ungulates. When he showed me 
his newly discovered skeleton in 1889, I was especially struck 
by the perissodactyl character of the carpus and tarsus, and 
considered it best to leave the genus in the Perissodactyla as “ an 
aberrant form, with nearest affinities to Palaeosyops and gen- 
era of that line.” It has also been doubtfully placed near the 
Perissodactyla by Flower and Lydekker. 
Depéret has now advanced sufficient evidence to exclude the 
edentate idea entirely and shows clearly that the resemblances 
which Chalicotherium bears to the sloths are purely superficial. 
As shown above the adaptations of the phalanges for prehension 
or digging involve an entirely different set of muscles from those 
employed in either the Cats or the Edentates. This genus has 
attained a somewhat similar functional result by a different 
route—a case of analogy but not of homology. So with the 
elongation and curvature of the fore-arm, the ultimate coales- 
cence of the ulna and the radius, the backward direction of 
the olecranon, the cleft ungual phalanges. All these are inde- 
pendent and “ parallel” or “homoplastic” adaptations. Chal- 
icotherium is still more positively separated from the Edentates 
by the numerous ungulate characters which it displays. 
Depéret is very much impressed by these ungulate structures 
and places this genus definitely among the Perissodactyla. - 
Let us, therefore, examine the ungulate hypothesis. Upon the 
affirmative side is the structure of the molar teeth; they cer- 
tainly bear a distant resemblance to those of Anoplotherium 
and a more striking likeness to those of Palæosyops and Titan- 
otherium. The reduction of the upper cutting teeth may be 
regarded as a secondary adaptation which does not affect the 
question of ungulate affinity either way. There are really 
several questions involved; shall we waive the structure of 
the terminal phalanges and call this genus an Ungulate? 
Shall we then direct our attention upon the teeth and carpals 
and tarsals and call it a Perissodactyl,or shall we follow Cope 
and remove it entirely to the Unguiculata? Let us sum up 
some of its leading characters: 
