xii INTRODUCTION. 
over the base of the culmen. Depth of bill is also measured with dividers, and is a 
measurement requiring extreme care. Length of tarsus is measured with dividers, 
one point resting in the tibio-tarsal joint, on the outer side, the other on the lower 
edge of lowermost tarsal scutella, in front (in Passerine and certain Picarian and 
Raptorial birds), or to the more or less obvious transverse depression marking the 
line of separation between tarsus and base of middle toe (in most water birds and 
some others). Length of middle toe is always measured with dividers from the 
last-mentioned point to the base of the claw, on top, and not including the claw, 
unless so stated. 
Measurements of eggs represent the average of six specimens (more or less, ac- 
cording to the extent of the series available for the purpose) which represent or 
approximate the average size and form as nearly as could be determined by the eye 
alone. 
THE NAMES OF COLORS used in the diagnoses are adopted from the author's “ No- 
menclature of Colors,”! in which may be found an elaborate though concise treatise 
on the subject, designed especially for the uses of the naturalist, and in which 186 
colors, embracing all that are named in descriptive ornithology, are depicted, by 
hand-colored plates. 
InLustRations.—With the exception of those which have already appeared in 
the Review of American Birds,” History of North American Birds? and Water Birds 
of North America, the illustrations have been made specially for the present work 
by Mr. John L. Ridgway, under the author's supervision, and engraved by the cele- 
brated “Jewett” process of Messrs. Matthews, Northrupp & Co., of Buffalo, N.Y. 
ACKNOWLEDGMENTS are specially due to Professor Baird, not only for the 
1A | Nomenclature of Colors | for Naturalists, | and | Compendium of Useful Knowledge | for Ornitholo- 
gists. | By | Robert Ridgway, | Curator, Department of Birds, United States National Museum. | With ten 
colored plates and seven plates | of outline illustrations. | Boston : | Little, Brown, and Company. | 1887. | 
[In this work is also embodied a “ Glossary of terms used in descriptive ornithology,” in which references 
are given to all the plates. The latter include, besides those representing the colors, three showing the exter- 
nal anatomy or “ topography” of a bird, with special reference to the names used in descriptions, one illus- 
trating various egg-contours, one showing a comparative scale of standard measurements, and two upon which 
are depicted the various forms or patterns of feather-markings. There is also, among other things useful to 
the naturalist, a series of tables for the easy conversion of inches and decimals into millimetres, and vice versa.] 
2 Smithsonian Miscellaneous Collections. | —181— | Review | of American Birds, in the Museum of the | 
Smithsonian Institution. | By | 8. F. Baird. | —Part I. North and Middle America. | —[Medallion.] Wash- 
ington : | Smithsonian Institution. | 
One volume, 8vo; date of publication (by signatures), June, 1864, to June, 1866, 
3A | History | of | North American Birds | by | S. F. Baird, T. M. Brewer, and R. Ridgway | Land Birds 
| Hlustrated by 64 colored plates and 593 woodcuts | Volume I [—III]. [Vignette.] | Boston | Little, Brown, 
and Company | 1874. | 
[This is the most recent work on North American ornithology, giving, besides technical descriptions, 
synonymy, ete., a general account of the history and habits of each species, as known up to date of publica- 
tion. The size is small 4to, and the total number of pages nearly 1800.] 
4 Memoirs of the Museum of Comparative Zodlogy at Harvard College, Vols. XII. and XIII. The Water 
Birds of North America. By S. F. Baird, T. M. Brewer, and R. Ridgway. Issued in continuation of the pub- 
lications of the California Geological Survey. J.D. Whitney, State Geologist. Boston. Little, Brown, and 
Company, 1884. 
[Two volumes, uniform in general style, typography, etc., with the “History of North American Birds,” 
and in reality the conclusion of that work. Total number of pages 1104, embellished by numerous wood-cuts.] 
