INTRODUCTION.
I hate first to express to the Trustees of the British Museum, and to
all Ornithologists, my regret for the delay which has occurred in finishing
this fifth volume of the ‘Hand-list .’a. The work was commenced in 1898,
and the first volume published in 1899 : it has, therefore, occupied ten,
years in completion. Although the whole of it had to be written in
my private time, I imagined th at five years would have been ample to
finish the book,, being at the rate of one volume every year. The
increased number of students in the Bird-Section of the Museum has
taken up so much of my official time, that my private time has been
largely occupied with Museum correspondence, and recently I have
seldom been able to find any leisure wherein to write the ‘ Hand-list.’
Some exception has been taken to my recognition, as species, of all
the forms described as sub-species, or races with trinomial names. My
views on this subject have often been stated, and as for trinomials,
I look upon the system as destructive. I consider that the burden
imposed upon the Zoologists who follow this method for the naming of
their specimens will become too heavy, and the system will fall by its
own weight. That races or sub-species of birds exist in nature, no one
can deny, but, to my mind, a binominal title answers every purpose,
and a system of nomenclature which calls the Hawfinch, Coccothraustes
coccothraustes coccothraustes, and the Common Swift, Apus ripus opus, will