Classification of Birds. 77 



of birds, each modification or peculiarity being illustrated by a charac- 

 teristic wood-engraving. The various modifications of form, exhibit- 

 ed in the wings and tail, the great organs of aerial motion, occupy 

 the greater portion of the next chapter. The principal varieties 

 of the form of the wings are considered under the heads of acumi- 

 nated, as in the Swallows, Terns, &c ; Falcate, a form possessed by 

 some of the Humming-Birds ; Pointed, as in the Crows, Flycatchers, 

 &c. ; Rounded, as in the common Wren, and also in most of the 

 Rasorial order ; Ample, as in the Heron, and in the genera Rupicola, 

 Promerops, &c The last are the Abortive or Abbreviated wings, 

 as in the Cassowary, Apteryx, Penguin, &c. In the tail, the other 

 great organ used in flight, the modifications are even more numerous 

 than those of the wings ; he enumerates and describes no less than 

 fourteen, under the titles of Even, Rounded, Fan-shaped, Graduated, 

 Cuneated, Arcuated, Spathulate, Slender, Forked, Lyre-shaped, Boat- 

 shaped, Compressed, Plumed, and Scansorial, all of which are 

 minutely described, and contrasted with each other in a manner 

 which cannot fail to be understood, on consulting the figures which 

 accompany the text. The various modifications of those essential 

 organs the feet are next considered, and to this part of the 

 work we would direct the especial attention of the student, as it 

 is in a great measure from the leading variations in their structure 

 that the primary characters of the orders are derived, and besides 

 natural groups are generally indicated by the subordinate modifica- 

 tions they undergo. 



In the raptorial foot he points out some peculiarities in the re- 

 lative position of the toes, which appear to have been overlooked, 

 but which mark a striking distinction between the foot of birds 

 belonging to this order, and that of the typical Insessores. Of the 

 feet of this latter order he gives a detailed description, and shows 

 how beautifully each change is in accordance with the economy of 

 its members. We particularly direct attention to the gradations of the 

 scansorial form of foot, which he has traced with a precision and 

 minuteness that shows an intimate and thorough acquaintance with 

 the subject. The remainder of this portion of the volume is taken up 

 with observations on the voice and nests of birds. In regard to the 

 voice, though agreeing with the author in many of his remarks, we 

 think that the song of birds, or its equivalent, is more connected 

 with the feeling of love or the reproduction of the species than he 

 seems willing to allow. We believe it, in the first instance, to be given 

 to the male for the especial purpose of attracting the females; at the 

 same time we don ot deny its exercise, in such birds as possess it 



