556 IIIRUNDO. SWALLOW. 



with two marginal series of feathers, their bare edges crenate. 

 External aperture of the ear rather large and elliptical. 



The general form is slender ; the body short, ovate, rather 

 compressed ; the neck short ; the head ovate, with the fore part 

 flattened. The feet are extremely short and slender ; the tarsus 

 extremely short, bare or feathered, but always with some dis- 

 tinct scutella below. The toes are feathered, or bare and pre- 

 cisely similar to those of the Sylvise and other birds of that 

 family, being of moderate length, slender, and much com- 

 pressed ; the first stouter, with two joints, the second with 

 three, the third with four, the fourth with five, the second and 

 fourth equal, the third much longer, and connected with the 

 fourth at the base. Claws rather long, moderately arched, 

 laterally grooved, tapering to a very acute point. 



Plumage soft, blended, glossy on the upper parts, the feathers 

 oblong, those on the fore part of the head short ; the bristle- 

 feathers at the base of the upper mandible very small. Wings 

 extremely long and pointed ; the quills and coverts with very 

 strong elastic shafts ; the quills eighteen ; the secondaries rather 

 short, incurved, broad, and deeply emarginate ; the primaries 

 tapering to a rounded point, the two outer longest, and a little 

 incurvate towards the end. Tail varying in length and form, 

 of twelve feathers, and even or forked. 



The Swallows form a very numerous genus of birds, varying 

 in size from that of a AVillow Wren to that of a Song Thrush, 

 and inhabiting both continents, but all residing in the tropical 

 regions during the winter, and only some migrating towards 

 the poles in summer. They live on insects, which they catch 

 on wing, and therefore are furnished with the means of per- 

 forming the most rapid and gliding flight. Their feet being 

 small and feeble, they are scarcely able to walk on the ground, 

 and seldom alight there, even to drink, but sip the water as 

 they skim over its surface, and bathe by dipping into it while 

 on wing. They fasten their nests to walls or rocks, or place 

 them in holes and other concealed stations. They are often 

 externally composed of solid materials, such as earth or sand 

 agglutinated in pellets, and are lined with straws, feathers, and 

 other soft substances. The eggs are generally four or five, 



