558 U. S. P. R. R. EXP. AND SURVEYS—ZOOLOGY—-GENERAL REPORT. 
Family CORVIDAE. 
Cu.—Primaries ten ; the first short, generally about half as long as the second (or a little more) ; the outer four sinuated on 
the inner edge. The nasal fossae and nostrils usually more or less concealed by narrow stiffened bristles, (or bristly feathers,) 
with short appressed lateral branches extending to the very tip, all directed forwards. Tarsi scutellate anteriorly, the sides 
undivided (except sometimes below) and separated from the anterior plates by a narrow naked strip, sometimes filled up with 
small scales. Basal joint ef middle toe united about equally to the lateral, generally for about half the length. Bill generally 
notched. 
The preceding characters distinguish the family of crows quite markedly from all others. In 
some respects there is a resemblance to the Paridae or Titmice, especially among the garruline 
birds ; the nature of this relationship will hereafter be adverted to. The features of the 
bristles of the bill, and the separation of the lateral and anterior scales by a narrow interval, 
are worthy of particular attention. The commissure is without the obtusely angular bend near 
the base, seen in the Icteridae. 
There are some genera of Corvidae with the nostrils not covered by bristly feathers, such as 
Psilorhinus, Gymnorhinus, Gymnokitta, &e. 
There are two sub-families of Corvidae represented in America, one embracing the true crows, 
the other the jays. They pass very insensibly into each other, and it is difficult to mark the 
dividing line. We may, perhaps, restrict the Corvinae to such forms as have a long bill, equal 
to the head; the tail short, and nearly even; the wings long and pointed, considerably longer 
than the tail, the tip formed by the third, fourth, and fifth quills. The Garrulinae are birds of 
smaller size, shorter wings, which do not exceed the graduated tail, and are sometimes much 
shorter ; the tip of the wing formed by the fourth, fifth, and sixth quills. Where Gymnokitta 
should come is a little uncertain, but probably among the true crows. 
In most genera of Corvidae the inner lateral claw is a little larger than the outer, and pro- 
jects beyond it; in the true crows they reach about to the same point; generally the lateral 
claws extend as far as the base of the middle one; the hinder is longer. 
The row of small scales is usually present on both sides of the tarsi in the Corvinae, but in 
the jays is generally restricted to the inner face. 
Sub-Family CORVINAE. 
Cu.— Wings long and pointed ; longer than the tail, and, when closed, reaching nearly to its tip, extending far beyond the 
under tail coverts ; the third, fourth, and fifth quills forming the tip of the wing. 
The character given by Swainson of lateral toes equal in Corvinae and unequal in Garrulinae, 
is subject to much uncertainty of determination. The features mentioned above, if not defining 
a natural sub-family, at least apply well to three genera of North American Corvidae. The 
following diagnosis may serve to distinguish them. 
A. Nostrils large, covered by bristly feathers ; wings reaching the tip of the rounded tail. 
Corvus.—Color throughout black. Bill thickened ; culmen very much curved. Bristly 
feathers at base of bill half as long as culmen. 
Pictcorvus.—Color, grayish. Whigs and tail above, black; lateral feathers white. Bill 
slender, attenuated, decurved. Bristly feathers at base of bill one-fourth the culmen. 
B. Nostrils small, completely exposed ; wings reaching to the posterior fourth of the nearly 
even tail. 
Gymnoxrtta.—Color, nearly uniform dull blue. 
