262 The Creodonta. (March, 
In geological time the Mesonychidz, Miacidæ and Oxyanite — 
are confined to the Eocene period. The Hyznodontide extent 
through the Upper Eocene and Oligocene or Lowest Miocene 
formations. The Centetidz are predominately Eocene, but i 
North America they are also found in the Oligocene. In recent 
times they are only known in the islands of Madagascar and 
Cuba. The Chrysochlorididz are modern and African, while the 
Talpidz commence in the Middle Miocene in Europe, and area 
abundant in recent times in the Northern hemisphere. Mytho- 
myidæ are only known as recent in África. These relations miy 
be expressed as follows: 
Eocene. Miocene. Recent, 
Lower, Upper. Lower. 
Mesonychid 
Hyænodontidæ .., “a | 
Chrysochlorididz, 
Centetidz 
eee ee ees 
"ee ease — _ 
z 
D 
5 
Ou 2 
8 
eee 
Americal 
MESONYCHID#. 
In this family the form of the inferior molars is not very dif 
ent from that displayed by the last lower premolars 0 i 
ous Mammalia generally. The superior molars are er pt 
pondingly simple structure, in like manner resembling © 
premolars of the superior series of Carnivora and some 
first, Ù 
also differ from those of Mesonyx in the development a J 
terior cusp, thus approaching the Hyznodontide (Fig: hos 
