56 Mr. W. Evans on the Periods 



Newton, and through him to Dr. Gadow. Tiedemann^s 

 Tohime and the earlier of Thienemann's two I have not seen, 

 and the references to these works are based on extracts 

 (rendered in English) wliich Professor Newton has very 

 kindly made for me. The Professor points out that Tiede- 

 mann gives no scientific names, but merely the German 

 vernacular ; and that while he has done his best to render 

 them correctly by the help of Naumaun, he cannot guarantee 

 that he has in every instance given the right equivalent. I 

 am further indebted to Professor Newton for a number of 

 /references to Naumann^s great work on the birds of Germany, 

 which is doubtless the origin of most of the periods given by 

 subsequent authors. Mr. Sclater's record of the duration of 

 incubation in the case of birds which have bred in the gardens 

 of the Zoological Society, contained in the Society's ' Proceed- 

 ings ' for 1859 (p. 205), and a very similar list given in the 

 second volume of Owen^s ' Anatomy of Vertebrates ' (p. 257), 

 supply much valuable information regarding non-European 

 species. In addition to these, isolated statements are to be 

 found in almost every work in which the habits of birds find 

 a place. To have exhausted anything like the whole of the 

 possible sources of information was an impossibility in the 

 time at my disposal. Still I have been able to consult a 

 goodly number of volumes, and the bulk of the material 

 they have yielded (no small quantity) will be found in the 

 right-hand side of the Table. No doubt much of it cannot 

 be relied on, while not a little is in all probability mere 

 repetition ; and it is therefore not without considerable hesi- 

 tation that I reproduce it so fully. Looking, however, to 

 the present position of the subject, there is, it seems to me 

 much to be said for the course I have adopted. 



A list of the works quoted will be found at the end of the 

 paper. When Thienemann is quoted, the reference is to his 

 * Fortpflanzungsgeschichte,' unless otherwise stated. 



The arrangement and nomenclature adopted in the Table are 

 based on the 'B. O. U. List of British Birds' and Sclater's 

 ' List of Animals in the Zoological Gardens ' (] 883) . In the 

 case of most of the American birds the A. O. U. List has 

 been followed. 



