558 U. S. p. R. R. EXP. AND SURVEYS — ZOOLOGY GENERAL REPORT. 



Family CORVIDAE. 



Ch. — Primaries ten ; the first short, generally abont half as long as the second (or a little more) ; the outer four sinualed on 

 the inner edge. The nasal fossae and nostrils usually more or less concealed by narrow slifluned 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 of 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 resemhlance 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 

 Psilorliinus, Gymnorliinus, Gymnohitta, &c. 



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. 



Ch. — 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-i'amily, 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. 



CoKVUs. — Color throughout black. Bill thickened ; culmen very much curved. Bristly 



feathers at base of bill half as long as culmen. 

 PicicoRVUS. — Color, grayish. Wnigs and tail above, black; lateral feathers white. Bill 



slender, attenuated, decurved. Bristly featliers at base of bill one-fourth the culmen. 



B. Nostrils small, completely exposed ; wings reaching to the posterior fourth of the nearly 

 even tail. 



Gymnokitta. — Color, nearly uniform dull blue. 



