116 THE AMERICAN NATURALIST. (VoL. XXXII. 
In fact, I am not at all certain that Colodon is found in Europe, 
even in beds above the Eocene. The Protapirus douvillei, which has 
been referred by some American paleontologists to Colodon, is, as I 
have shown,’ really a true tapir and belongs in the genus Protapirus, 
which is one of the generic links leading to Tapirus. 
Again, Hyrachyus intermedius of Filhol has been placed by M. 
Gaudry as a synonym of Co/odon minimus. I can hardly agree with 
my learned friend of the Jardin des Plantes in this identification, 
and I think the jaw and teeth referred by Filhol to the genus 
Hyrachyus were correctly identified. 
In the jaw of the French species of Hyrachyus, described by 
M. Filhol, the number and structure of the teeth are the same as 
in the typical American species of this genus, and there is no third 
lobe on the last lower molar. The measurements of the jaw and 
teeth of Æ. intermedius correspond nearly exactly with those of 
Hyrachyus agrarius of the Bridger. 
The presence of such typical American Middle Eocene genera as 
Hyrachyus and Isectolophus in the Eocene of Argenton, France, 
demonstrates how closely this fauna is related to that of the 
Bridger. 
So far as I am aware, the larger species of Lophiodon are not 
found at Argenton, Z. sselensis coming from Issel. We might 
conclude from this that the Argenton beds are really earlier than 
those of Issel, and this would harmonize better with our ideas of 
the dental morphology of the tapirs, as it is more probable that 
the types with a convex metacone, Isectolophus, gave origin to both 
tapirs and lophiodonts than that the latter were ancestral to the 
tapirs. The typical forms of Lophiodon, as Z. ésselensis, prob- 
ably led to no permanent results in regard to evolving higher 
genera. 
In conclusion, the evidence is now pretty conclusive that Hyrachyus 
is found at Argenton, and a decided advance has been made by Pro- 
fessor Gaudry in the removal of one of the small species of Lophiodon 
from that genus, but whether the view is correct that it is a species 
of Isectolophus remains to beseen. The third species of Lophiodon 
which was referred by Cuvier to this genus is now placed by Pro- 
fessor Gaudry in Propaleotherium. The mist has now considerably 
cleared away in regard to What is Lophiodon? In France, at least, 
all of the small species have been accounted for and referred 
probably to their proper genera. 
1 Science, Dec. 25, 1896. 
