NOTICES OF NEW BOOKS. 231 



the operation of classification by ^diagnosis. It is in the applica- 

 tion of these principles that the value of Mr. Seebohm's work lies. 



In each group as diagnosed by him we find a combination of 

 characters not to be found in any other group ; in other words, 

 characters which are diagnostic of that group alone. The linear 

 arrangement, therefore, which he has adopted in setting down the 

 names of these groups (beginning with the Passeres and ending 

 with the Struthiones) is of secondary importance, because the 

 order in which they are named may be altered in accordance with 

 the views of the reader without affecting the constitution of the 

 groups themselves. 



The great point is to be able to write down an unfailing diag- 

 nosis for each so-called " Suborder," and then to group these in 

 a smaller number of " Orders ;" the larger division of " Sub- 

 classes" (such as Passeriformes, Falconiformes, Anseriformes, &c.) 

 we are inclined to regard as unnecessary. Indeed we would go a 

 step further, and for the sake of simplicity abandon the names of 

 Mr. Seebohm's " Orders," and apply that classificatory term to 

 his " Suborders." With the " Class" Aves divided into thirty-six 

 " Orders" (Mr. Seebohm's "Suborders"), each having its compo- 

 nent " Families," comprising allied " genera," or groups of 

 " species," we should have a sufficiently detailed classification, 

 and get rid of such practically superfluous terms as " Sub-class," 

 " Sub-order," " Sub-genus," and " Sub-species." 



The traveller who has a few broad landmarks to guide him in 

 the exploration of a country hitherto untraversed by him, 

 stands less chance of losing his way than if he attempts to carry 

 out a multiplicity of minute directions which can only tend to 

 confuse him. So it must be with the student of Zoological 

 Classification. For teaching purposes the simpler the scheme of 

 classification the better. Details may be filled in afterwards. 



A Handbook of European Birds, for the use of Field Naturalists 

 and Collectors. By James Backhouse, Junior. Small 8vo, 

 pp. 334. London : Gurney & Jackson. 1890. 



It was a happy thought on the part of Mr. Backhouse to plan 

 a Handbook of European Birds in one volume. There was a 

 distinct opening for such a work, and English visitors to the 

 Continent would be especially grateful for a good guide on this 

 subject. But the book which Mr. Backhouse has written is not, 



