1894. SOME NEW BOOKS. 63 



Lyell's " Principles." It also gives an outline of certain recent 

 discoveries in mountain structure, and on the origin of the crystal- 

 line schists ; though this part is scarceh' up-to-date. 



The fourth part commences with an account of meteors and the 

 earth's beginning, leading to chapters on historical geology. All this 

 section seems to be compiled from various Vv^-ell-known text-books, 

 and would be improved by more thorough revision. The final section, 

 *' On some Theoretical Questions, "contains four disconnected chapters, 

 which we cannot help thinking would be better placed in the sections 

 to which they properly belong, for other equally theoretical questions 

 have been discussed in various parts of the volume. The four 

 chapters thus isolated refer to "The Age of the Earth," " The Per- 

 manence of Ocean Basins and Land Areas," " Climatal Change : its 

 cause and history," and " The Distribution and the Descent of Life." 



We have, perhaps, criticised this book somewhat more severely 

 than we should otherwise have done if the author had not 

 challenged comparison with Lyell. The mantle of Lyell has not 

 descended to Professor Bonney ; but if unscientific readers wish for 

 a popular " Story of our Planet," we can safely recommend the 

 present work. 



Dr. H. G. Bronx's Klassex uxd Ordnungen des Thier-Reichs. Band, vi., 

 Abtheilung iv. Aves. II. Systematischer Theil. By Hans Gadow, Ph.D., 

 F.R.S. 8vo. Pp. 303. 



Dr. Gadow, in the concluding parts of the above-mentioned work, 

 adds the keystone to his long labours, which, it is not too much 

 to say, will prove of incalculable benefit for all time. 



Those who are familiar with the anatomical section of this book 

 will naturally turn to the present volume with great expectations ; 

 and assuredly they will not be disappointed, for they will find that, 

 what has ever proved a subject of extraordinary difficulty and 

 com.plexity, whether regarded from the limited horizon of the 

 Ornithologist, or the more extended range of the Biologist, has been 

 treated with a thoroughness that will claim at once the gratitude and 

 the admiration of all workers in this field. 



By reason of the plan adopted by Dr. Gadow of presenting 

 us with tables of comparison between the various orders and families 

 and pithy " conclusions," it is possible to trace, step by step, the 

 ground over which the author has passed in the construction of 

 his present scheme — a boon v/hich we shall not sufficiently appreciate 

 till we recollect the painful groping in the dark, and fruitless pursuit 

 of phantom probabilities, that must necessarily have been involved in 

 a research of this nature. 



Substantially, the present arrangement is the same as that which 

 appeared in the Proc. Zool. Soc, 1892, enlarged and improved. 



Thus the Class Aves is now divided into two sub-Classes, Archae- 

 ornithes and Neornithes; and three divisions, " Neornithes Ratitae," 

 " Neornithes Odontolcae," and " Neornithes Carinatae." The third 

 division is divided into two brigades of two "legions" each, the 

 Colymbomorphae and Pelargomorphae comprising the first, and the 

 Alectoromorphae and Coraciomorphae the second brigade. To the 

 Colymbomorphae belong the Ichthyornithes, Colymbiformes, Sphenisci- 

 formes, and Procellariiformes : while the Pelargomorphae embrace 

 the Ciconiiformes, Anseriformes, and Falconiformes. The Alectoro- 

 morphae contain the Tinamiformes, Galliformes, Gruiformes, and 



