144 Recently published Ornithological Works. [Ibis, 



for Mr. J. E. Thayer, who described them iu the ' Auk ' for 

 1911. In the present volume Mr. J. Dixou gives us some 

 further particulars of the breeding and other habits of this 

 bird as observed by him at Providence Bay, also in north- 

 eastern Siberia, and adds some interesting details of its 

 distribution and status as a North American bird. 



Mr. C. J. Hawkins contributes an article on " Sexual 

 selection and bird-song,'' in which he criticizes Darwin's 

 theories of sexual selection and suggests that the cause of. 

 song- lies in the internal life of the bird rather than in 

 external causes. He believes that bird-song as well as 

 many other manifestations of secondary sexual characters 

 is due to the ripening of the gonads and the setting free of 

 hormones which stimulate the nervous system and thus 

 cause the nuptial display. This argument from the so- 

 called hormones^ which are entirely hypothetical and the 

 existence of which have never been proved, does not appear 

 to us to entirely invalidate Darwin's theory of sexual 

 selection, but we must leave the reader of Mr. Hawkins's 

 paper to draw his own conclusions. 



A number of faunal papers dealing with different districts 

 of the North American continent are of more local interest, 

 but we must mention ''A list of birds collected on the 

 Harvard Peruvian Expedition of 1916," by Messrs. O. Bangs 

 and G. K. Noble, in which are described a number of new 

 species and races, while there are several rectifications of 

 taxonomy and synonymy. 



Avicultural Magazine. 



[The Avicultural Magazine. Edited by Graham Reushaw, M.D. 

 Third Series. Vol. ix. November 1917 to October 1918.] 



The last completed volume of the 'Avicultural Magazine' 

 shows no signs of diminishing interest in matters avicultural, 

 though it was found necessary, in consequence of the scarcity 

 and increased cost of paper as well as the great rise in the 

 price of printing, to diminish the size of the monthly num- 

 bers from June onwards, but we understand that an increase 



