Reviews — Bollo's Eocene Chelonians. 521 



volume iii. are modestly stated by himself under fifteen heads, in- 

 cluding such matters as the discovery of the Laramie genus Champso- 

 saurus in Tertiary beds, the discovery of Tertiary allies of Plagiaulax, 

 the discovery of five families and many genera of Creodonta, the 

 discovery of the Periptychidee, the Meniscotheriidge, the Phenaco- 

 dontidse, the discovery of characters of the suborder Condylarthra, 

 the characters of the Pantolambdidae, of the suborder Taligrada, 

 of the Anaptomorphidse, the reconstruction of Hyracotheriam and 

 Hyrachus, the discovery of many Marsupials in the Lower Miocene, 

 and of ancestors of the Cats and Dogs ; to which may be added the 

 description of three hundred and forty-nine species, all discovered by 

 the author, except thirty-two. But although the present volume may 

 not claim to have first set forth the greater results to which these are 

 but some of the stepping-stones, we may point to the method of com- 

 parison of the fossil types with each other and with living genera as 

 indications of the sources of knowledge by which the grouping of 

 families and genera has been produced, which has given rise to new 

 ordinal and sub-ordinal groups and improved classifications. The 

 conception of the Bunotheria will always remain one of the most 

 interesting of these results, because it is the first attempt to apply 

 the principles of evolution to Mammalian classification in its larger 

 grouping. The Amblypoda introduces a new hoofed type of life, 

 which was already elaborated by the descriptions of Coryphodon, 

 given in Lieutenant Wheeler's Survey in 1877. These and a 

 multitude of minor innovations in classification are the fruits of new 

 knowledge gathered partly from animals still living, partly from 

 the wonderful organisms discovered in United States rocks. It 

 is not too much to say that the light thus thrown upon the Mammalia 

 as a whole, is more instructive as to the laws of life, and the condi- 

 tions under which the component structures of animals have varied, 

 and been evolved, than the insight gained during the same time by 

 the study of Embryology. This harvest of fruit from the past may 

 justify the confidence that in the history of fossil life, which has yet 

 to be told by the paleontologist, the significance of the varied 

 organization of existing animals will be demonstrated. 



H. G. Seelet. 



II. — M. L. Dollo on new Chelonians from the Eocene of 



Belgium. 1 



IN these two memoirs the learned Assistant Naturalist to the Eoyal 

 Belgian Museum of Natural History describes two new genera 

 of Chelonians which are of very considerable interest, and also pub- 

 lishes a synopsis of the classification of the order, which is a modifi- 

 cation of that proposed by Prof. E. D. Cope, of Philadelphia. 



1 " Les Cheloniens du Bruxellien (Eocene Moyen) de la Belgique," Bull. Mus. R. 

 Hist. Nat. Beig. vol. iv. 75-86, pis. i. ii. (1884), "Les Cheloniens Landeniens 

 (Eocene Inferieur) de la Belgique," Ibid. pp. 129-141, Avoodcuts. 



