In accordance with the scheme of the Series generally, the order followed runs from the lowest forms and the Ratite Birds upwards; the Carinate Birds being divided, after Dr. Gadow's plan, into two Brigades or main sections, and these again into Legions, Orders, and so forth. It should, however, be understood that the _Species_ of each Genus are often merely placed in the most convenient order; and that, where a geographical range is given, it does not follow that it is unbroken from end to end. In descriptions of colour, the names used for tints in the British Museum Catalogue of Birds have been commonly adopted, or for British species those in Mr. Howard Saunders' _Manual of British Birds_. Various subjects of a highly technical, or at least of a special character, have purposely been avoided in the main, as unfitted to the scope of the work; such are, Variation and Hybrids, with their accompaniments of Dimorphism, Dichromatism, and the like; Myology; Mechanism of Flight and the supposed Lines of Flight on Migration; the Classifications of Linnæus and the older writers; and the Strickland Code of Ornithological Nomenclature. For these Professor Newton's _Dictionary of Birds_, and especially the Introduction to it, may be consulted; besides a multitude of other works. The woodcuts have been chiefly supplied by Mr. G. E. Lodge; but a few illustrations have been utilized from other sources. The author does not hold himself responsible for the fact of the Family names being in Roman in place of Italic type, nor for the dissociation of the vowels in the diphthongs; in these minor points he personally differs from the writers of the former volumes, though he agrees with the wish of his Editors for uniformity. {vii}In conclusion, he must take the opportunity of acknowledging the invaluable assistance afforded by Mr. Howard Saunders, who carefully went over the whole of the proofs, while Dr. R. B. Sharpe was kind enough to do the same; nor must he fail to record his indebtedness to Professor Newton, Mr. Sclater, Dr. Gadow, Mr. Ogilvie Grant, and many others, not to mention the innumerable authors without whose previous labours to write a book of this description would be a well-nigh impossible task. Dr. Stejneger's Volume on Birds in the _Standard Natural History_ should be mentioned in particular. A. H. EVANS. CAMBRIDGE, _November 17, 1898_. {viii}ADDENDUM Since the text has been printed off, several new species have been described, and of these it is necessary to mention at least the following;– _Archaeopteryx siemensi_, from Solenhofen, where the original form was obtained.–(Dames.) _Euryapteryx exilis_ (Dinornithidae); a new genus, _Anomalornis_, is also proposed for _Anomalopteryx_ (preoccupied).–(Hutton.) _Ammoperdix cholmleyi_ (Phasianidae), from Suakin.–(Ogilvie-Grant.)