The deposits of Eocene age are less numerous, and spread over a far more limited area, than those of the Miocene period, and only restricted portions of them furnish any remains of land animals. Our knowledge of the Eocene mammalian fauna is therefore very imperfect and will not occupy us long, as most of the new types it furnishes are of more interest to the zoologist than to the student of distribution. Some of the Eocene mammalia of Europe are, however, of interest in comparison with those of North America of the same age; while others show that ancestral types of groups now confined to Australia or to South America, then inhabited Europe. _Primates._--The only undoubted Eocene examples of this order, are the _Cænopithecus lemuroides_ from the Jura, which has points of resemblance to the South American marmosets and howlers, and also to the Lemuridæ; and a cranium recently discovered in the Department of Lot (S.W. France), undoubtedly belonging to the Lemuridæ, and which most resembles that of the West African "Potto" (_Perodicticus_). This discovery has led to another, for it is now believed that remains formerly {125}referred to the Anoplotheridæ (_Adapis_ and _Aphelotherium_ from the Upper Eocene of Paris) were also Lemurs. Some remains from the Lower Eocene of Suffolk were at first supposed to be allied to _Macacus_, but were subsequently referred to the Ungulate, _Hyracotherium_. There is still, however, some doubt as to its true affinities. _Chiroptera._--In the Upper Eocene of Paris remains of bats have been found, so closely resembling living forms as to be referred to the genus _Vespertilio_. _Carnivora._--The only feline remains, are those of _Hyænodon_ in the Upper Eocene of Hampshire, and _Pterodon_, an allied form from beds of the same age in France; with _Ælurogale_, found in the South of France in deposits of phosphate of lime of uncertain age, but probably belonging to this period. Viverridæ (civets) are represented by two genera, _Tylodon_, the size of a glutton from the Upper Eocene, and _Palæonyctis_, allied to _Viverra_, from the Middle Eocene of France. The Canidæ (wolves and foxes) appear to have been the most ancient of the existing types of Carnivora, five genera being represented by Eocene remains. Of these, _Galethylax_ and _Cyotherium_ were small, and with the existing genus _Canis_ are found in the Upper Eocene of France. _Arctocyon_, about the size of a wolf, is a very ancient and generalised form of carnivore which can not be placed in any existing family. It is found in the Lower Eocene of France, and is thus the oldest known member of the Carnivora.