648 Recently published Ornithological Works. 



the present epoch, want to be " up to date," and to keep them 

 waiting until February 1904 for a list of the works published 

 in 1901 is much too long a delay. The ' Zoological Record ' 

 for 1901 was issued in December 190*2, and although we may 

 allow " a little law " for the commencement of a new under- 

 taking, fifteen months more could hardly have been required, 

 if due diligence had been used. 



The Authors' Catalogue, which, as already mentioned, 

 forms " part i." of the seventeenth volume of the ' Inter- 

 national Catalogue of Scientific Literature,' contains, besides 

 a Preface and an Introduction, a list of the titles of all 

 zoological works published in 1901 arranged alphabetically 

 according to the names of the authors. If complete (which, 

 however, as we shall presently prove, is by no means the 

 case), it would be a very useful work, as it shews (or should 

 shew) exactly what books and papers on zoological subjects 

 have been published during the year in question. The 

 " Authors' Catalogue " fills 260 pages, with double columns, 

 aud contains 5918 titles which are numbered consecutively. 

 We suppose that these titles have been supplied by the 

 "Regional Bureaus" of the different countries and have been 

 arranged in order by the Central Bureau in London. 



The second part of the ' International Catalogue,' called 

 the " Subject Catalogue," is based entirely on the Authors' 

 Catalogue, and in fact contains nothing more than the 5918 

 titles of the " Authors' Catalogue " rearranged in different 

 ways according to their subjects. It consists of 1158 pages 

 with double columns. The whole subject of Zoology is, as we 

 are informed in the Explanatory Preface, divided into 29 

 " Branches" besides a " Comprehensive Branch," which 

 includes works of a general character. We turn over the 1158 

 pages of the " Subject Catalogue" to find our favourite subject 

 " Aves." This is rather a hard task, as no running titles are 

 given on the tops of the pages — only mysterious numbers 

 from 0010 to 6031. To ascertain the meaning of these 

 curious numbers Ave must turn again to the Explanatory 

 Preface, where we learn (p. 21) that the titles of literature 

 on "Aves " are numbered from 5803 to 5831. By this clue 



