INTRODUCTION. 



group; but the fourth (Co7)oj)0]ohagidce) was left to he constituted 

 by Porbcs — his, not less able, successor in the Zoological Society's 

 Prosectorshij). 



As in the case of the Olicjcimjodo', I have not attempted in 

 treating of these four families to invent any new arrangement, but 

 have in general simply followed out the lines laid down in the 

 * Xomenclator Avium Xeotropicalium.' The time has not yet 

 arrived for a fresh revision of these obscure forms of Passeres. 

 Not only a much fuller series of skins, but, what is much more neces- 

 sary, a complete collection of specimens preserved in spirit and the 

 still more important adjunct of an able and experienced anatomist are 

 required before any such new revision can be successfully carried out. 

 Had I'orbes and Garrod been still living to continue their labours 

 this might have been ere now possible ; but -where is a successor to 

 be found with similar zeal and skill and with equal opportunities? 

 Not, I fear, in the author of the present volume, who is fully aware 

 that his work has no claims to be called a monograph, but is simply 

 a catalogue of species and specimens, which it is hoped, however, 

 may tend towards the elucidation of a very difficult subject by 

 future labourers. 



In the present volume I have catalogued about 448:^ specimens 

 of Tracheophonce as belonging to the Collection of the British 

 Museum. These have been referred to 92 genera and 531 species, 

 leaving only 28 species known to the author but not yet represented 

 in the Collection. Many other species, however, indicated only by 

 the footnotes under the head of each genus, may ultimately turn 

 out to be perfectly valid. The " types " in this portion of the series 

 are especially numerous, and amount to no less than 172. These 

 are in great part derived from what was formerly my own private 

 collection, which I am much pleased to see incorporated in the great 

 National Series, and from that of Messrs. Salvin and Godman, which 

 is also very rich in original specimens. I must also call atten- 

 tion to the extreme value of the Salvin-Godman Collection as regards 

 the localities of the specimens, which are in most cases authenti- 

 cated by known collectors and in many instances exhibit nearly the 

 whole range of the species. Nor must I omit again to record the 

 obligations I am under to the same generous friends, to whose 

 liberality the National Collection is so deeply indebted, for their 



