CYPSELIN^. 71 



SELIN.E, HIRUNDIN^E, and CAPRIMULGIN,E, enter into this 

 order. 



FAMILY IV. CYPSELINJE. CYPSELINE 

 BIRDS, OH SWIFTS. 



Body moderate ; neck very short ; head roundish, de- 

 pressed. Bill extremely short, weak, opening to beneath 

 the hind part of the eyes, compressed at the end ; upper 

 mandible with the dorsal line convex, the tip declinate ; 

 lower mandible much smaller, with the angle very large, 

 the dorsal line slightly convex, the tip slender. Mouth 

 very wide ; palate nearly flat, covered with minute pa- 

 pillae ; tongue short, triangular, fleshy, sagittate and pa- 

 pillate at the base, with the tip obtuse, or somewhat bifid ; 

 oesophagus wide above, then of moderate breadth ; sto- 

 mach elliptical, its muscular coat of moderate thickness, 

 epithelium dense, rugous ; intestine extremely short, 

 rather wide ; no cceca ; cloaca large, ovate. Trachea 

 without inferior laryngeal muscles. Eyes large. Nostrils 

 oblong, basal, approximate. Apertures of ears rather 

 large. Feet extremely short ; tarsus stoutish ; four toes, 

 all directed forwards, the outer three all nearly equal ; 

 claws rather large, stout, decurved, very acute. Plumage 

 rather compact above, blended beneath ; no bristles about 

 the mouth ; wings extremely elongated, falciform, the 

 first or second quill longest. Tail of ten feathers, mo- 

 derate or long, but much exceeded by the wings. 



The Swifts are remarkable for the extreme rapidity of 

 their flight and unwearied activity. They feed exclu- 

 sively on insects, which they seize in open flight, and 

 therefore migrate southward in autumn. They reside in 

 holes and crevices of rocks and buildings, laying from 

 two to five very elongated white eggs. Having no inferior 

 laryngeal muscles, they are destitute of song, but utter a 

 loud shrill scream. 



