PREFACE. 



Work, I should probably at the present moment be inclined to reduce still further the genera of a few 

 of the subfamilies. It must also be remembered that I have endeavoured to adopt such names only 

 as may be supposed to designate genera ; those of the lower divisions or subgenera are given under 

 the names of the species which form their type ; and I have added the synonymous names of the genera 

 as well as those of the subgenera, in the form of notes to the generic name employed. 



The difficulties in the way of defining the value of a division are indeed very great, and its adoption 

 must always depend much on individual opinion, as well as on the extent of our knowledge of species ; 

 for an isolated species often appears to form the basis of a good division when examined by itself, while 

 the distinction vanishes at once when the bird is examined in connection with the entire mass of species 

 forming the group to which it belongs. Genera, too, are not unfrequently established on unique 

 specimens which are difficult of access, and have been recorded without the aid of figures to give an 

 accurate idea of their forms ; but of such I may state that there are only a very few instances in which 

 I have not had the good fortune to obtain the means of examining either the specimens themselves or 

 drawings made from them. Great caution is also required in dealing with genera established, as some 

 have been, on falsified or distorted specimens, such, for instance, as Erolia, Barbilanius=Sparactes, 

 Hyreus, Autrochenon, and Anarhynchus ; to which I may add Vemdia, which I have recently learned 

 is considered to have been established on a pigeon furnished with wax wattles and a false tail, for which 

 reason it becomes necessary to blot out this genus from among the Gourince. 



Great obstacles frequently occur in the way of ascertaining the true and pi-oper (that is to say, the 

 earliest-employed) generic names, many having been first published in Transactions, Journals, Books 

 of Travels, and even more miscellaneous works, which have not been much examined for this purpose 

 until of late. I may mention two examples illustrative of this difficulty, which require correction in 

 the present Work. I had been led to suppose that Phaleris of M. Temminck (1820) was the oldest 

 name for the division to which I have applied it in the body of the "Work ; but I have lately found that 

 that division was proposed in the previous year (1819) by Merrem in " Ersch und Grub. Encycl." under 

 the name of Simorhynchus : and I have been informed by Dr. Hartlaub (who was indebted for the 

 information to the Prince of Wurtemburg) that the division for which I have adopted Mr. Swainson's 

 name of Calurus (1837) was proposed as far back as 1801 by Pedro de la Llave, in a Mexican 

 publication entitled " Registro trimestre," under the name of Pharomachrus. 



Such changes with regard to generic names must continually take place until our knowledge of all 

 that has been done by previous writers becomes registered in a general work, by means of which 

 the information thus eventually obtained by dint of continued application cannot fail to become the 

 foundation of that most desirable object, a uniform system of nomenclature. 



The Index of Generic Names referred to in this Work will be found to extend to upwards of 2400 ; a 

 greater number than has been recorded in any previous publication. Of the genera adopted (amounting 



