502 Prof. K. A. von Zittel—On the Mammalia. 
tobos, Bubalus, Elephas, Ursus, Canis) appear to have wandered 
from out of Asia, and these, together with the numerous forms of 
Deer, which were already split up into several sub-genera, chiefly 
contribute the peculiar character of the Pliocene fauna. In spite 
of their modern habitus, the Pliocene forms are linked uncon- 
ditionally to the older forerunners of the Miocene period, and of not 
a single order can it be asserted that the thread of continuity between 
Miocene and Pliocene has been completely broken. But in a far 
higher measure than previously the dawn of the present time is 
reflected in the forms of the Pliocene Mammalia. With the exception 
of some mostly imperfectly known representatives of the microfauna, 
the only Pliocene genera which are wanting in the present period 
are Hipparion, Mastodon, Hyenarctos, Machairodus, Lepiobos, and 
Dolichopithecus. A much greater number of genera have indeed 
forsaken their Huropean dwelling-places and withdrawn into warmer 
regions. Tropical Africa and India are the places of refuge in which 
a considerable portion of the Pliocene genera were preserved, and 
in the course of time more or less transformed. No single Pliocene 
species has maintained itself unchanged to the present. That the 
Pliocene fauna of India agreed in character with that of Europe is 
evident from the fact that the Upper Sivalik beds and the newer 
deposits in the valleys of. the Kistna, Narbada, Jumna, Godavari, 
and Pemganga, contain not only the same genera, but partly even 
identical, or nearly identical, species. 
The Cetacea, Pinnipedia and Sirenia, which are present in great 
abundance in the Crag deposits of Antwerp, Holland, and Suffolk, 
and in the Marine sub-Apennine beds of Italy, occupy a similar 
intermediate position between the Miocene and the Present to that 
of the land fauna. They contain the following genera :— 
CETACEA. Ly periodon. SIRENIA. 
Squalodon. Choneziphius. Felsinotherium. 
Eurhinodelphis. Flacoziphius. LHalitherium. 
Priscodelphinus. Dioplodon. 
Delphinus. Berardiopsis. PINNIPEDIA. 
Steno. Plesiocetus. Pristiphoca. 
Tursiops. Leterocetus. Paleophoca. 
Orca. Amphicetus. Mesotaria. 
Globicephalus. LTerpetocetus. Callophoca. 
Physeter. Lidiocetus. Platyphoca. 
Physeterula. Mesocetus. Phocanella. 
Flomocetus. Lsocetus. Gryphoca. 
Physodon. Balenoptera. Trichechus. 
Scaldicetus. Megaptera. Alachtherium. 
Hoplocetus. Balena. 
? Priscophyseter. Faleocetus. 
? Physotherium. 
In North America the so-called Loup Fork or Pliohippus beds of 
Niobrara, Nebraska, Wyoming, Colorado, Kansas, New Mexico, 
Texas, and Mexico, are usually reckoned to the Pliocene, and they 
are especially characterized by the abundance of Mastodon, Aphelops, 
Hipparion, Pliohippus, Protohippus, Merychyus, Merycocherus, Camels, 
Rodents, and Carnivora. The absence of Elephas, horned Ruminants, 
