Mr. E. D. Cope on the Bunotherian Mammalia. 23 
character gives little ground for systematic determination 
among Hocene Mammalia, and has deceived paleontologists 
from the days of Cuvier to the present time. The only con- 
necting-point where there may be doubt as to the ungulate 
or unguiculate type of a mammal is the family Periptychide, 
of the suborder Condylarthra. The suborder Hyracoidea 
may furnish another index of convergence. 
The families included in these suborders will be the fol- 
lowing :— 
Tantoponra. Calamodontide, Ectoganide. 
Tittoponta. Tillothervide. 
DAUBENTONIOIDEA. Chiromyide. 
Prosimim. Tarstide, (?) Anaptomorphide, (2) Mixo- 
dectide, Lemuride. 
Insectivora,  Soricide, Lrinacetde, Macroscelide, 
Tupaide, Adapide*, Arctocyonide. 
Creoponta. Yalpide, Chrysochloridide, Esthonychide, 
Centetide (= Leptictide olim), Oxyenide, Miacide, 
Amblyctonide, Mesonychide. 
I at one time called this order by the name Insectivora, a 
course which some zoologists may prefer. But a name should 
as nearly as possible adhere to a group to which it was first 
applied, and whose definition has become currently associated 
with it. Such an application is correct in fact, and is a 
material aid to the memory. ‘There are various precedents 
for the adoption of a new general term for a group composed 
of subordinate divisions which have themselves already re- 
ceived names. 
In order to determine the number of internal tubercles in 
some of the Insectivora, so as to ascertain the affinities of some 
questionable genera, it 1s first necessary to examine the homo- 
logies of the cusps of the molar teeth. The opossums are 
characterized by the presence of three longitudinal series of 
tubercles on the superior molar. The homologies of these 
cusps are rendered clear by the character presented by the 
fourth superior premolar, where the anterior intermediate is 
wanting. ‘lhe external cusps are really such, and are not 
developed from a cingulum external to the true external cusps, 
* Two species of Pelycodus must be removed from this genus and 
family and be placed in the Creodonta with Mvoclenus. They are the 
P, pelvidens and P. angulatus, which have the posterior inner tubercle of 
the superior molars a mere projection of the cingulum. I place them in 
anew genus, which differs from Mcoclenus in the possession of an internal 
cusp of the fourth inferior premolar, under the name of Chriacus, type C. 
pelvidens, 
