CYPSELINiE. 71 
SELiNJE, HiRUNDiNiE, and Caprimulgin^, enter into this 
order. 
FAMILY IV. CYPSELINiE. CYPSELINE 
BIRDS, OR 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- 
pillse ; 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 coeca ; 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. 
