158 MOTACILLIN^. MOTACILLA. 
straight, the edges inflected, the tip acute ; gape-line 
straight. Both mandibles internally concave and narrow, 
with a median prominent line ; tongue very slender, emar- 
ginate and finely papillate at the base, flat, tapering to a 
slit point ; oesophagus narrow, uniform ; proventriculus 
oblong ; stomach a gizzard of considerable power, round- 
ish or elliptical, with distinct lateral muscles, and dense, 
thin, longitudinally rugous epithelium ; intestine short, 
of moderate width ; coeca very small, cylindrical. Nos- 
trils elliptical, or oblong, in the lower and fore part of the 
nasal depression, which is feathered at the base. Eyes 
of moderate size. Aperture of ear large, transversely oval. 
Feet of ordinary length, slender; tarsus much compressed, 
the outer slightly united at the base ; claws of moderate 
length, curved, or long and slightly curved, extremely 
compressed, acute. Plumage soft and blended, the fea- 
thers ovate, of loose texture ; wings rather long, broad, 
of eighteen quills, the first obsolete, the next three nearly 
equal, and longest; one of the inner secondaries very long; 
tail long, of twelve narrow feathers. 
These birds reside in pastures and meadows, frequent 
the sides of streams and lakes, or the sea-shore, run with 
great celerity, and almost constantly vibrate their body, 
like the Totani. Their flight is rapid and undulating ; 
their voice shrill. They feed on insects, larvae, and small 
Crustacea and mollusca. They are allied to the Saxicolae 
and Sylviae on the one hand, to the Alaudinae on the other. 
GENUS LI. MOTACILLA. WAGTAIL. 
Bill of moderate length, slender, straight, a little broader 
than high at the base, compressed toward the end, its upper 
outline slightly declinate at the base, then straight, and at 
the end very slightly decurved, the notches obsolete, the tip 
acute. Tongue very slender, sagittate and papillate at the 
base, tapering to a slit point ; oesophagus of moderate width ; 
stomach oblong, compressed, with the muscular coat thick, 
