iv PREFACE 
(2nd ed.), the latter is also given and placed second. Thus 
no inconvenience can arise. Where subspecies are clearly 
recognised trinomials are given, it being obviously incorrect, as 
a general rule, to give a description as specific which may in 
part not apply to the whole species but only to one or more of 
its local forms.' 
The classification adopted follows generally that of Professor 
Hans Gadow in Bronn’s Thier-Reich: Vogel IL. 
My best thanks are due to the Rev. F. C. R. Jourdain and 
to W. Farren of Cambridge for revising the proofs and for 
valuable suggestions, 
All the illustrations are by Mr. A. W. Seaby, except those of 
the heads of the crow and rook, and one or two others, repro- 
duced from the British Bird Book. | 
1 Binomial: Corvus corax. Trinomial: Corvus corax corax, the 
first name being that of the genus, the second of the species, the 
third of the subspecies, the last being added to distinguish various 
local forms or races: e.g. the typical Corvus corax corax from Corvus 
coraxz hispanus (Spain) ; Corvus corax varius (Fzeroes), &c. 
