552 THE POPULAR SCIENCE MONTHLY. 



which were entirely new. This was followed by numerous accounts 

 of mammals, birds, and reptiles, which were largely inspired by the 

 study of the specimens which Alcide de Orbigny, Eydoux, Soleyet, 

 Castelnaud, and other travelers brought back from their long voyages. 

 The examination of the series of birds led him to general conclusions 

 respecting their natural division. These conclusions, drawn from the 

 character of the skeleton, and particularly of the sternum, have been 

 widely accepted. He interested himself in the study of the geo- 

 graphical distribution and classification of reptiles, in the course of 

 which he made various investigations upon the batrachians, particularly 

 the ealamanders and tritons. In connection with his researches in the 

 fishes, he was in charge for twenty years of the administration's ex- 

 periments in pisciculture in the department of Herault, the chief ob- 

 ject of which was to acclimatize the true salmon, species which were 

 not known to exist in any of the streams emptying into the Mediter- 

 ranean. In co-operation with M. Walckenaer, he prepared a " Natural 

 History of Wingless Insects" ("Histoire naturelle des Insectes 

 apteres "). ' 



M. Gervais's first work in paleontology was the thesis which he 

 prepared for the degree of Doctor in Science, on fossil birds. In it he 

 demonstrated the existence, in the Tertiary period, of birds belonging 

 to several genera common in the present age. Cuvier had proceeded 

 in this line of investigation hardly further than to give approximately 

 the order, and in only a few cases the possible genus to which his 

 specimens might belong. M. Gervais, having better material at his 

 command, was able to make more precise determinations. 



In fossil mammalia he made known a new simian, the Semnopithe- 

 cus monspessulanus, a hyena, several deer, a porcupine, and numerous 

 cetaceans. His memoir on the distribution of the fossil mammalia 

 among the several Tertiary beds of France deserves particular men- 

 tion. It exhibited the association of the different species among the 

 various faunas that succeeded one another, from the earliest Tertiary 

 epoch, corresponding with the lignites of the Soissonais to the period 

 of the large animals whose remains are found in the breccia of the cav- 

 erns. The author shows that these different faunas, which he makes to 

 number seven, never lived simultaneously, either in France or any other 

 country, and that no species was common to more than one of them. 

 The fauna which left its bones in the breccia is the only one which is 

 not entirely extinct. Some of these faunas present only animals of ter- 

 restrial species, while others furnished in some of the beds both marine 

 and land species. This feature gave useful indications for determining 

 by the comparison of the land species buried in the marine beds with 

 those which are found at other places in fresh-water deposits, the con- 

 temporaneity of land and marine animals for each epoch. It also enabled 

 M. Gervais to determine, under certain conditions, the comparative 

 age of the two kinds of formations. Contrary to the opinion of some 



