222 RevieiDs — Prof. A. Gaudry — The Evolution of Mammalia. 



to appreciate and understand the nature of the discoveries they 

 achieved. 



Thus at Pikermi in Attica ; in the far Western States of America ; 

 at Sansans, Allier, Leberon, and other localities in France, such 

 great and important additions have been made of late to our know- 

 ledge, that it has even been found possible to speak with some 

 confidence of the Evolution of the Mammalia since their first 

 appearance in numerical importance in the Cainozoic period of our 

 Earth's history. 



After twenty years of research among the Tertiary Mammalia, 

 Professor Gaudry has become convinced that the infinite diversity 

 of forms which they manifest are the result of one dominant plan 

 resulting from a Supreme Intelligence. This plan is made intelli- 

 gible by Evolution, which enables him to demonstrate the relation to 

 each other of the mammals of which remains are found in the suc- 

 cessive Tertiary deposits. He devotes, as a rule, a chapter to each 

 ordinal group, and begins with the Marsupials. In this notice we 

 shall follow him through the ten chapters into which the book is 

 divided, so as to set forth the more striking results at which the 

 author has arrived as the reward of researches which, in this depart- 

 ment of palaeontology, have not been surpassed by any investigator. 



There are no Herbivorous Marsupials in the Tertiary rocks ; and 

 it is urged that, from the way in which the movements of the parent 

 are controlled by the helpless condition of the young, this Order 

 would be at a disadvantage in the struggle for existence, as compared 

 with the higher herbivorous mammals ; and that this disadvantage 

 would lead to their extermination in the European Tertiary area. 

 In the older Tertiaries of Paris, Auvergne, and Vaucluse, Carnivo- 

 rous Marsupials are found which so closely resemble the existing 

 Opossums that at present it is not easy to separate them by generic 

 characters. 



Hyoenodon and Pterodon, though in their dentition somewhat inter- 

 mediate between the Placental and Implacental types, are inferred 

 to have been Marsupials on the evidence of the form of the axis, 

 which closely resembles that of the living American species DidelpMs 

 cancrivora. This intermediate character is borne out by several 

 other genera, such as Falceonictis, and CynoTiycenodon or Provivercea 

 found in the Phosphorites of Quercy. Arctocyon has been shown by 

 Gervais to be an Omnivorous Marsupial, resembling the Bears. It 

 is found impossible to understand this blending of characters in the 

 Tertiary genera except upon the hypothesis that the Implacental 

 mammals of the Secondary rocks became ultimately developed into 

 the Placental type, and it is in this way that the author is disposed 

 to explain the many resemblances to Marsupials shown in fossil 

 Garni vora, living Lemurs and other animals. 



The types of marine mammalia are not numerous. Squalodon in 

 the Miocene, and the many Cetaceans of the Antwerp Crag. This 

 evidence does not justify any conclusion as to the parentage of the 

 Cetacea. Ealitheriim is an intermediate type between the Dugong 



