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FAMILY XIII. — MOTACILLUSLE. WAGTAILS. 
Bill of moderate length, straight, slender, a little broader than high at 
the base, compressed toward the end ; upper mandible with the dorsal line 
sloping, a little convex toward the end, the nostrils slight, the tip acute ; 
lower mandible with the angle rather long and narrow, the dorsal line 
ascending and scarcely convex, the edges somewhat involute, the tip acute. 
General form slender ; head ovato-oblong ; neck short. Feet of ordinary 
length, slender ; toes very slender, the lateral equal, the outer adherent to 
the base, the hind toe rather large ; claws rather long, arched, compressed, 
acute, that of the hind toe generally very long. Plumage soft and blended. 
Bristles small. Wings long and pointed, one of the minor secondaries often 
much elongated aud tapering. Tongue sagittate, slender, with the tip slit ; 
oesophagus uniform ; stomach a very muscular gizzard, roundish, with large 
tendons, and thin rugous epithelium, intestine of moderate length ; coeca 
very small. Trachea simple, with four pairs of inferior laryngeal muscles. 
This family is connected with the Turdin® by Seiurus, and with the 
Alaudin® by Anthus , which are the only two American genera. 
Genus I.— SEIURUS, Swains. WOOD- WAGTAILS. 
Bill rather short, straight, slightly broader than deep at the base, com- 
pressed toward the end, the edges a little inflected, the dorsal lines of both 
mandibles slightly convex, the notches very slight, the tip acute. Nostrils 
basal elliptical. General form slender; head ovato-oblong. Feet of ordinary 
length ; tarsus slender, compressed, covered anteriorly with a long undivided 
piece and three inferior scutella ; toes of moderate length, slender ; the first 
a little stouter than the third, the inner slightly shorter than the outer, 
which is adherent at the base ; claws of moderate length, very slender, much 
compressed, moderately arched, acute. Plumage soft, blended. Bristles 
very small. Wings of moderate length ; the first or outer quill little shorter 
than the third, which is longest. Tail of moderate length, even. 
