NOTICES OF NEW BOOKS. 277 



forcing air through the glottis, which in this creature, as in the 

 Frog, is closed during the intervals of breathing. 



In this place the puffing and hissing of birds are very 

 properly considered. From original battle-cries the author 

 passes on to alarm-notes, and in this connection we have the first 

 suggestion that Evolution is now proceeding in the formation 

 of a long cry, by the utterance of a shorter one many times 

 repeated in quick succession. Instances are given of the 

 occasional construction of such alarm-phrases by the Blackcap, 

 Long-tailed Titmouse, Nightjar, and other birds, leading to the 

 development of habitually long alarms, like those of the Black- 

 bird, Mistle Thrush, and Magpie. 



Chapter II. deals with the influence of combat, including 

 rivalry and emulation ; and here we note a suggestion that certain 

 of the Finches may include in their songs sounds which indicate 

 defiance. Hence singing during combat, as exhibited by various 

 species, is also considered. 



Chapter IV. deals with the call-note; and here we find a 

 complaint of the lack of attention on the part of ornithologists, 

 who, it seems, have been too ready to call any prominent note a 

 " call-note," such, for instance, as the pink of the Chaffinch, 

 which Mr. Witchell shows to be more correctly describable as a 

 "battle-cry." It is suggested that the first call-notes were mere 

 cries of distress inherited by the young, and retained by them as 

 advantageous after leaving the nest. In song-birds the tones 

 might have been " gradually affected by any recurrent prevalent 

 sounds falling on the receptive senses of successive generations 

 of the young." 



Chapter V. deals with " the simplest songs," and these the 

 author finds to be at present mere repetitions of call-notes 

 uttered in varied intervals of pitch ; in many more elaborate 

 songs the call-note is still retained and frequently employed. 

 Thus the Sky Lark, Nightingale, Goldfinch, House Sparrow, 

 Titmice, Brown Wren, and others, utter their call-notes in their 

 songs. The inference is that in some species the song was 

 originally developed from mere repetitions of the call-note. 



In dealing with " noticeable incidents " of bird-song, the 

 author clears the ground of side-issues, before entering upon 

 the more important themes of heredity and imitation. The 

 " incidents " cover a wide range of subjects — the influence of sex, 



