﻿86 



ON THE CLASSIFICATION OF BIRDS. 



length of their secondary and tertial quills. In another 

 fissirostral genus, Collar is > which includes the short- 

 billed rollers, there is an evident falling off of the typi- 

 cal perfection ; some of the primaries and secondaries 

 are indeed notched, yet the first quill feather is shorter 

 than the second and third ; but in the genuine rollers 

 these notches disappear, the primaries are much shorter, 

 and the second, third, and forth quills are nearly of 

 equal length. We have not been an T eye-witness to the 

 manner of flight of either of the two last-named genera, 

 nor does any author appear to have noticed them. 

 There can be no question, however, that the rollers not 

 only are fissirostral birds, that is to say, taking their 

 food on the wing, but that they immediately and natu- 

 rally follow the short-billed rollers ; the structure of 

 their mouth and feet completely disproving the assertion 

 of some authors, that they live, like magpies, by search- 

 ing for insects upon the ground. It will be unnecessary 

 to notice the different representations of the fissirostral 

 type of wing, seeing that it is generally combined in 

 such types with other characters, too intricate to be 

 well understood by the student. 



(79-) II. The falcated, or sword-shaped form of 

 wing, is only possessed by the numerous family of hum- 

 ming-birds (fig. 43.). It differs from that last described 



by the two or three first primaries being curved towards 

 their ends, which are rather suddenly rounded off, w T hile 

 all the others which succeed them are pointed. The 

 primaries are certainly developed even more than in the 

 swallows ; a circumstance which is decidedly favourable 

 to the idea that these bird are the swiftest. The whole 

 strength of the wing, it may almost be said, is thrown 

 into these feathers, for the shortest, which is of course 



