190 
JOUKNAL OF MAMMALOGY 
Joleaud, L. Les migrations des mammiferes Americains et Apricains a 
TRAVERS LES REGIONS AtLANTIQUES PENDANT LES TEMPS NeOGENES. ReVUe 
generale des Sciences, Paris, vol. 30, pp. 704-713, figs, (maps) 1-9, December 
30, 1919. 
Professor Joleaud is convinced that free interchange of mammalian life be- 
tween North America, Africa and Europe took place during the Tertiary period 
by way of land masses occupying much of the area of the present Atlantic Ocean 
and persisting intermittently as late as the beginning of the Pliocene. He pre- 
sents the reasons for this belief in a paper accompanied by nine maps showing 
the exact transatlantic courses pursued by the following mammals: (1) the 
zalambdodont Insectivora (from western North America to the West Indies, 
western Africa, and Madagascar, with a side branch to southern South America), 
(2) the Kalohatippus-Anchitherium group of horses (from Oregon to Spain and 
China); (3) the archaic mastodons (from the Mediterranean region to Florida), 
(4) the Hipparion group of horses (from Florida westward across North America 
and eastward to Europe, northern Africa, China), (5) the Old World porcupines 
(from South America by way of the West Indies to Spain and west Africa; thence 
to Indo-China), (6) The Hippotragine antelopes (from the Mediterranean region 
to the southern United States and Nebraska), (7) the Procyonidm (from North 
American to South America and from southern Florida to the Mediterranean 
region, England and southeastern Asia), (8) the Leporidce (from Texas to the 
Mediterranean), (9) the Tragelaphine antelopes (from the Mediterranean region 
to Nevada). The text is no less positive than the maps. “It is also by the 
Atlantic route,” Professor Joleaud writes (p. 708-709), “that the genus Hystrix 
migrated into the Old World. This rodent, which originated in South America, 
could not have crossed by way of North America, practically no mammal of 
La Plata having entered that country between the Montien and the Astien. The 
family Hystricidce was represented in the lower Miocene, in Patagonia, by the 
genera Acaremys and Steiromys related to existing Argentinian types. Arboreal 
in the New World these animals have become burrowers in Africa, in the south 
of Asia and of Europe, exactly like another African rodent, Xerus, which origin- 
ated in North America and came to France in the Tortonian. The migration of 
porcupines from South America to Africa and then to Europe probably took 
place at a geological period which was not favorable to arborescent vegetation, 
perhaps under the influence of a steppe climate like that of the Pontien.” This 
passage may be taken as representative of the entire paper. I have chosen it 
for translation and analysis merely because it deals with a group on which I 
have recently been working. 
That the genus Hystrix or the family Hystricidce originated in America there 
is no evidence. No American fossil has yet been found that certainly represents 
either the genus, the family, or a type which is directly ancestral. A few fossil 
teeth resembling molars of Hystrix are known from the Miocene of North America; 
but in the absence of the essential parts of the skull the systematic position of 
the animals represented by such fragments is impossible to determine with cer- 
tainty, though at present the species are referred with little doubt to genera re- 
lated to the beavers. The South American Acaremys and Steiromys were mem- 
bers of the families Echimyidce and Erethizontidce respectively. These two 
groups, like all the other American families of Hystricoidae, are not yet known to 
