INTRODUCTION. 137 



horse and camel, and was finally able to restore the skeletons 

 of these extinct genera. Then it became evident that both 

 genera had comprised several species, and gradually the 

 fossil remains of other genera intimately allied to these were 

 discovered in the Middle and Upper Eocene strata at Issel 

 (Aude), Buchsweiler (Alsace), and in the Upper Eocene 

 marls in various localities. In the same way as he had 

 investigated the Ungulata, Cuvier also investigated fossil 

 remains belonging to Carnivora, and determined their 

 relationship with living representatives. 



Cuvier was wholly convinced of the unerring accuracy of 

 his comparative methods. It is told of him that on one 

 occasion when a fossil skeleton came into sight in the Paris 

 gypsum layers, he at once declared it to belong to the genus r> 

 Didelphys, an American opossum. A number of his colleagues ( 

 were sceptical of this, and in order to prove it, Cuvier indicated j 

 the exact place where the characteristic marsupial bone on the 

 pubis ought to be found in the rock, and in presence of his 

 colleagues worked out the part from the surrounding rock, and 

 displayed it to their astonished eyes. 



The third volume concludes with the description of a 

 number of bird, reptile, and fish remains. The fourth volume 

 contains treatises on the remains of horses, pigs, and 

 rodents in the Pleistocene deposits and bone breccias of 

 Gibraltar; on Carnivora in the bone caves of Germany and 

 Hungary ; on some genera of the Edentate Order, Bradypus, 

 Megalonyx, Megatherium; on Sirenia or "sea-cows"; on 

 "sea-dogs" or the Phocidte family of the Carnivora; and 

 finally, a survey of all known fossil reptiles. In this as in 

 the other volumes, every chapter on fossil types is preceded 

 by an exhaustive exposition of the structures of allied living 

 forms. 



In the whole literature of comparative anatomy and 

 palaeontology there is scarcely any work that can rank with 

 this great masterpiece of Cuvier. It passed through four 

 editions, each edition containing additional chapters. The 

 last (1834-36), edited by his brother Friedrich Cuvier, consists 

 of ten volumes' of text and two volumes of illustrated plates. 



The "Preliminary Discourse" of the first volume later bore 

 the title of " Discourse on the Revolutions of the Surface of 

 the Globe," and was translated into several European languages. 

 In it Cuvier gives expression to his views on the origin and 



