404 Prof. K. A. von Zittel—On the Mammalia. 
I. Lowest Eocene. 
Already in the intercalated fresh-water beds in the neighbourhood 
of Rheims, belonging to the Lowest Hocene, a very remarkable 
fauna has been discovered by Lemoine.’ Only the genera Neo- 
plagiaulax and Liotomus are linked to the Allotheria of the Upper 
Chalk, the remaining constituents of the ‘Fauna of Cernays” belong 
to the Placental mammalia. Small Insectivora (Adapisorex) and 
Carnivora (Creodontia) of a very primitive type (Procynictis, Dis- 
sacus, Hyenodictis, Tricuspiodon, Arctocyon, Conaspidotherium, Arcto- 
cyonides, Plesiesthonyx, Protoproviverra), which, indeed, with the 
exception of the prominently large Arctocyon, are only represented 
by very scanty remains ; farthee some five-toed ungulates of the 
order Condylarthra (Pleuraspidotherium, Or thaspidotherium), and 
two doubtful Lemurs (Plesiadapis and Protoadapis) compose this 
oldest Tertiary assemblage of animals in Hurope. 
A remarkably similar contemporaneous fauna comes from the 
‘«« Puerco-beds” of New Mexico. According to Cope? the vertebrate 
fauna of Puerco consists of twelve species of reptiles, one of birds, 
and ninety-three of mammals. Of these last, no fewer than 46 
belong to the Creodontia (Mioclenus, Tricentes, Chriacus, Proto- 
chriacus, Oxyclenus, Pentacodon, Goniacodon, Sarcothraustes, Delta- 
therium, Triisodon, Dissacus, Didymictis, and others), 24 to the 
Jondylarthra (Haploconus, Anisonchus, Zetodon, Hemithleus, Peri- 
ptychus, Ectoconus, Protoyonia), 2 to the Amblypoda (Pantolambda), 
5 to the Lemurs (Mixodectes, Indrodon), T to the Tillodontia 
(Psittacotherium, Hemiganus, Conoryctes, Onychodectes), and 11 to 
the Allotheria, amongst which the genus Polymastodon, is much 
larger than the associated genera Neoplagiaulax, Ptilodus and 
Chirox. The more varied composition of the American fauna 
corresponds with its greater abundance, but the only new 
order not present in the Huropean fauna is the Tillodontia, and 
this is probably already represented in the Upper Chalk by the 
genus Stagodon (Thleodon). If we review, as a whole, the 
mammals from Rheims and Puerco, we find, together with certain 
Allotheria continued from the Chalk (which here reach their maxi- 
mum and then disappear finally), and together with the puzzling 
Tillodontia, which die out in the Hocene, four different orders of 
Placental mammals (Creodontia, Condylarthra, Amblypoda, Pachy- 
lemuria). The typical representatives of these four orders in the 
Newer Eocene, where they first attain their complete development, 
stand, in external appearance and in their general organization, far 
from each other; the forms from the faunas of Cernays and Puerco, 
on the other hand, are connected together so closely by a number of 
features in common, that in many instances it is difficult to decide 
to which order they may belong. They all possess five-toed planti- 
1 Lemoine, V. Etude d’ensemble sur les dents des Mammiféres fossiles des environs 
de Reims. Bull. Soc. Géol. de France, 1891, 3 ser. xix. pp. 263-290. 
2 Cope, E. D., Synopsis of the Vertebrate Fauna of the Puerco Series. Trans. 
Amer. Philos. Soc. 1888, xvi. 
