﻿92 ON THE CLASSIFICATION OF BIRDS. 



the European genus, and are as long, and nearly 

 double the breadth, of the chief quills. This struc- 

 ture, with no very considerable variation, runs through 

 the greater portion of the rasorial or gallinaceous birds. 

 The quail, however, deserves a separate notice : its 

 powers of flight are well known to be far greater 

 than those of the partridge ; for it annually performs 

 two long migrations, on its passage from Africa to 

 Europe, and back again. We consequently find that 

 its wing unites the rasorial with the acuminated form ; 

 the first and second primaries being the longest, and 

 double the length of the secondaries : this union of the 

 two forms is also observable in the sand grouse of 

 Africa (Pterocles), whose wings, for the size of their 

 body, are much longer than those of any rasorial bird. 

 The only examples of the rasorial form of wing among 

 the Perchers, are restricted to the Trogons, the rasorial 

 type of the Fissirostres. 



(84.) Ample wings, which we shall now describe, 

 may perhaps be thought so closely allied to the rounded 

 form as not to deserve a separate character ; nevertheless 

 they produce a very different and peculiar sort of flight, 

 and are, consequently, formed upon a different model. 

 The heron is the most familiar example of this struc- 

 ture. In nearly all the species, the tertials are almost 

 equal to the scapulars ; but the secondary quills which 

 intervene rapidly diminish in length from the tertials, 

 and become very short where they join the last of the 

 primaries. Much of this form of wing, however, be- 

 longs to nearly all the natatorial and wading tribes ; but 

 in the herons, and other ample-winged birds, the pri- 

 maries are short, and the secondaries and tertials re- 

 markably broad : so that, although the flight is slow 

 and heavy, it is regular, lofty, and can be long sustained. 

 Any one who has seen the slow but steady course of the 

 heron, immediately perceives that it flies like no other 

 bird with which he is familiar, excepting, perhaps, the 

 lapwing, which has much of the same character. By 

 this broad expanse of wing the heron mounts high in 



