124 



GENERAL ORNITHOLOGY. 



the double-forked, a common style among sandpipers, as if each half of the tail were forked. 

 But in such case, the forking is slight, merely emargination, being little more than protrusion 

 of the middle pair of feathers in an otherwise lightly forked tail ; and in the double-rounded 

 form the gradation is seldom if ever great. 



I should also allude to shapes of tail resulting from the relative positions of the feathers. 

 Prominent among these is the complicate or folded tail of the barn-yard fowl, and others of the 

 Phasianidce, — a very familiar but not common form. It is only retained while the tail is 

 closed and cocked up, — for when it is lowered and spread in flight it flattens out. The oppo- 

 site disposition of the feathers is seen to some extent in our crow blackbirds (Quiscalus) , 



a where the lateral feathers 



slant upward from the lower- 

 most central pair, like the 

 sides of a boat fi-om its keel ; 

 this is tlie scaphoid (Gr. 

 (TKcKf))], a boat) or carinate 

 (Lat. carina, a keel) tail. 

 Our ''boat-tailed" grackle 

 has been so named on this 

 account. One of the most 

 beautiful and wonderful of 

 all the shapes of the tail is 

 illustrated by the male of the 

 lyre-bird (Menura superha, 

 fig. 32), in which the feathers are anomalous both in shape and in texture, and the resulting 

 form of the whole is unique. Various shapes, which the student will readily name from the 

 foregoing paragraphs, are illustrated in many other figures of this work. It should be remem- 

 bered that, to determine the shape, the tail should be nearly closed; for spreading will ob- 

 viously make a square tail round, an emarginate one square, etc. I append a diagram of the 

 principal forms (fig. 33). 



Fig. 33. — Diagram of sliapes of tail, adc, roumled ; aec. gradate; nic, 

 cuneate-gradate ; ale, cuneate; ahc, double-rounded; ./W/, square; fh(j, 

 emarginate ; /«eo(/, double-emarginate; kim, forked; Icem, deeply forked; 

 khm, forflcate. 



IV. THE FEET. 



The Hind Limbs, in all birds, are organized for progression — all can walk, run, or hop 

 on land, though the power to do so is very slight in some of the lower swimming birds, as 

 loons and grebes, and certain of the lower perching birds, as hummers, swifts, goatsuckers, and 

 kingfishers. They are specially fitted for perching on trees, bushes, and other supports requiring- 

 to be grasped, in the great majority of birds, as throughout the Passeres, Picarice, AccipitreSy 

 Columhce, and, in fact, many water-birds ; there being few forms, mainly found among three- 

 toed birds, or those in which the hind toe is short, weak, and elevated, in which the extremity 

 of the limb has not decided grasping power. The limb becomes a paddle for swimming either 

 on or in the water in many cases. In not a few, as parrots and birds of prey, the foot is 

 serviceable as a hand. Those kinds of birds which live in trees and bushes habitually 

 progress, even when on level ground, in a series of hops, or rather leaps, both feet being 

 moved together : in all the lower birds, however, the feet move one after the other, as in ordi- 

 nary walking or running. The modifications of the hind limb are more numerous, more 

 diverse, and more important in their bearing on classification than those of either bill, wing, 

 or tail; their study is consequently a matter of special interest. 



Their Bony Framework (fig. 34). — Beginning at the hip-joint, and ending at the 

 extremities of the several toes, the skeleton of the hind limb consists in the vast majority of 

 adult birds of twenty bones. This is the typical and nearly the average number; birds 



