31. Hirundo (Swallow). Bill short, depressed, very wide at base, commissure straight. Nostrils basal, oval, partly closed by membrane. Tail deeply forked, of twelve feathers, the outermost greatly elongated and abruptly attenuated. Legs and feet slender and bare; toes rather long, three in front, one behind; claws moderate.
32. Chelídon (Martin). Bill short, depressed, very wide at base, commissure slightly decurved. Nostrils basal, oval, partly closed by membrane and opening laterally. Tail forked, of twelve feathers, outermost not abruptly attenuated. Legs and feet slender, closely feathered above; toes rather long, three in front, one behind; claws moderate, sharp.
33. Cótile (Sand-martin). Bill short, depressed, very wide at base, commissure straight. Nostrils, wings and tail as in Chelidon. Legs and feet slender, and bare except for tuft of feathers on tarsus just above hallux; toes moderate, three in front, one behind; claws strong.
FAMILY FRINGILLIDÆ
(Finches)
Remarkable for the shortness, thickness, and powerful structure of the bill; the upper and lower mandibles are usually equally thick, and their height and breadth are nearly alike, so that the bill when closed presents the appearance of a short cone, divided in the middle by the gape. By its aid they break open the hard woody capsules and fruit-stones containing the seeds and kernels which form their chief food. At nesting-time many species live on insect larvæ, with which the young are almost exclusively fed. The wings have nine visible primaries. This family is one of immense extent, consisting of relatively small birds.
34. Ligurinus (Greenfinch). Bill compressed towards tip, with scarcely perceptible notch at point; nostrils basal, concealed by stiff feathers directed forwards; wings rather pointed, first quill obsolete, second, third and fourth nearly equal and longest. Tail rather short, slightly forked. Tarsus scutellate in front; toes moderate; claws arched and laterally grooved.