energy with which he threw himself into the work, it was manifestly 

 impossible for him single-handed to complete the Catalogue within any 

 reasonable time. The assistance of other ornithologists was hence 

 invoked to take up certain groups, to the study of which they had 

 been known to have specially devoted themselves. These were, in 

 the order in which their aid was given, Mr. Henry Seebohm, 

 Dr. H. Gadow, Mr. P. L. Sclater, Mr. 0. Salvin, Mr. E. Hartert, 

 Mr, W. R. Ogilvie-Grant, Mr. E. Hargitt, Captain Shelley, Count 

 Salvadori, and Mr. Howard Saunders. The special contributions 

 of each of these authors will be seen in the list of volumes and 

 their contents. Dr. Sharpe, however, did not relinquish his 

 labours on the Catalogue at the end of the fourth volume. Not 

 only did he materially assist in many of the volumes produced under 

 the names of other authors, but for seven more volumes (making 

 eleven altogether) he is entirely, and for two others he is partly, 

 responsible. Some indication of the amount of his share in the 

 whole work may be gained by the statement that out of 11,548 

 species described in the Catalogue 5181 are contained in Dr. Sharpe's 

 portion, and 6367 in those parts written by the ten other authors. 

 Acknowledgments of the liberal and ready assistance, either by 

 the donation or loan of specimens or communication of information, 

 rendered by numerous ornithologists, both British and foreign, 

 during the progress of the work, will be found in the Prefaces and 

 Introductions to the several volumes. 



The Catalogue is based, not only upon the immense collection of 

 birds in the Museum, but also upon all other available material 

 contained in public or private collections, or described in zoological 

 literature. It therefore professes to be a complete list of every bird 

 known at the time of the publication of the volume treating of the 

 group to which it belongs. Under the heading of each species is 

 (1) a copious synonymy : references being given to every mention of 

 it which occurs in standard books or journals. This has been a work 

 of prodigious labour, but it is hoped that, being fairly exhaustive, it 



