MAMMALIAN FATJXA OF THE YAL D ARNO. O 



district of Piacenza with the tyi^ical R. leptorhinus, Cuv. (i^ro parte), 

 in the district of Asti and the Upper Yal d'Arno with R. etruscus. 



In the same way the name Hippopotamus major has caused con- 

 fusion. The Postpliocene remains of Hippopotarnus are pretty 

 generally assumed to be the same as those of the Hipp>opotamus of 

 the Arno Valley, although such a union is not the result of recent 

 comparisons, but a survival of Cuvier's view of the matter, who did 

 not distinguish Pliocene and Postpliocene strata, but grouped them 

 together under the name of " couches meubles," and who accordingly 

 was predisposed to regard these fossils as identical. The species 

 H. major was founded on the perfect skull from the Arno Yalley, 

 preserved in the Plorentine ]5J[useum, and described by Cuvier and 

 Nesti ; and Cuvier pointed out the difference between it and the 

 living^, ampliihius. Under the same name he also cited remains of 

 Hippopotamus from caves &c., although they were not so perfect as 

 to justify such a decided statement. So long, then, as the remains of 

 the Hippopotamus from caves and from other Postpliocene deposits 

 are not proved to be identical with those of the Arno Yalley, it 

 seems unjust to designate the former as H. major. 



In many cases, where Eleplias meridionalis is cited from Post- 

 pliocene strata, there is a great probability of its being a variety 

 of E. antiquus. The latter does not appear in the Upper Arno Yalley, 

 but it occurs together with other Postpliocene mammals in the 

 neighbouring Yal d'Ambra (near Bucine) and in the regioii of Arezzo. 



In respect to the lignite of Leffe, in Lombardy, the greatest 

 care should be taken respecting conclusions as to the age of the 

 mammals ; because in one Italian museum fossils are labelled in 

 the most careless way, as coming from Leffe, while distinctly 

 showing that they are partly Miocene and partly Eocene. EUpTias 

 meridionalis and ^05 etruscus are the only mammals which I know 

 with certainty as coming from Leffe. 



§ 5. Relations to Living Form^. 



Among the thirty-nine mammals of the Yal d'Arno which I 

 mentioned at the beginning of this essay, we find at present five 

 genera which are extinct : — Machairodus, Mastodon. Leptohos, 

 PalcBOryx, Palceoreas. Not a single species is identical with those 

 living to-day. JSTotwithstanding this, we find among the mammals 

 of the Arno Yalley transitional forms towards those of Pleistocene 

 times. 



The former, however, show still nearer relationships to some 

 living faunas than to those of our Pleistocene. In dealing with 

 this question the Palfearctic, j^earctic, Neotropical, and Australian 

 regions cannot be considered, as there exist too few analogies for 

 the purpose, and only the Ethiopian and the Oriental region remain 

 open for our inquiry. Hippopotamus is, amongst our Pliocene 

 genera, the only one in the present day exclusively indigenous to 

 the Ethiopian region ; and on the other hand the genus Tapirus, 

 known in the Oriental region, is missing in the Ethiopian. Two 

 other genera. Castor and Arvicola, are represented in the Palaearctic 



