792 The Condylarthra. [August, 
cludes also the Hyracoidea.! This order realizes fully the antici- 
pation which I expressed in 1874, for the greater number of its 
species are pentadactyl and plantigrade, both anteriorly and pos- 
teriorly, and have tubercular or bunodont dentition. The order 
to which I have referred Phenacodus, the Taxeopoda, has been 
already defined in these pages.? It includes those curious mam- 
mals the Hyracoidea or conies, and is divisible into two sub- 
orders by the following characters : 
A sors ego aac no fibular facet of calcaneum, but an interlocking ors 
ee 
tion bet fibula and ei hn ungual phalanges truncate. ... yrat 
A mity process; no fibular facets on either calcaneum or naiiai ; a third 
. Cond} 
trochanter of the femur; sate phalanges acuminate 
IG, 1.—Dentition of EREE rhabdodon Cope, two-thirds 
a, safetie molars from below; 4, inferior molars from above 
natural size. Fig. 
m the Puerco 
beds of New Mexico. Original. From Vol. 11, Report U. 5. Geol. Survey Terri- 
tories. 
The astragalus in the sub-order Condylarthra is absolute 
distinguishable from that of the flesh-eating groups C Ti 
and Carnivora. The humerus also presents a character 0 
ly un- 
unguiculate orders, in possessing an epicondylar foramen, . 
is elsewhere unknown among ungulates. The humeral con i 
as the Ambly- 
have the generalized character of the same type d 
poda, and of the lower Perissodactyla, in lacking an p lows! 
crest’ The Condylarthra may then be further defined as si) 
Astragalus with one uniformly convex distal articular face 
merus with epicondylar foramen. This sub-order has aS 
1 AMERICAN NATURALIST, June, 1882 (May 17). American philo- 
2 AMERICAN NATURALIST, 1882 (May 2oth) p. 523. Proceeds. 
soph. Society, 1882, p. 444. 
3 AMERICAN NATURALIST, April, 1882, p. 334- 
4 AMERICAN NATURALIST, 1881, p. 1017, Nov. 29. 
