INTRODUCTION.
Tht3 present volume continues the list of the known species of Passeri-
formes down to the end of the Gerlhiiclce. Owing to the increasing
pressure of official work, it has taken longer to prepare than I anticipated,
the number of species described since the ‘ Catalogue of Birds ’ being
truly remai’kable, and requiring much time and labour for their
enumeration.
In my efforts to accomplish this object, I have been assisted, as before,
by a number of my brother Ornithologists, to whom the proofs of the
work have been submitted. I am especially indebted to the undermentioned
Naturalists for material help in this respect; and the reviews
of the genus Lanius by Mr. Ogilvie Grant, and of the Paridce by
Dr. Bianchi have lightened my labours considerably. The monograph of
the Paridce, Sittidce, and Gerthiidce, published by Dr. Hellmayr in the
I Tierreich,’ appeared after the present volume was in type, so that I have
not been able to avail myself of his conscientious work to the extent
which I should have wished. I have again pleasure in acknowledging
the assistance rendered by my chief attendant, Mr. Charles Chubb,
especially in the preparation of the Index.
The following gentlemen, who have revised the proofs of the present
volume, deserve my warm thanks for their assistance :—
England.—Dr. P. L. Sclater, Mr. Howard Saunders, Hon. Walter
Rothschild, D.Sc., M.P., Mr. Ernst Hartert, Mr. W. B.. Ogilvie
Grant, Dr. C. W. Andrews, and Mr. W. P. Pycraft.
France.—Prof. Dr. Oustalet.