236 MOTACILLA BOARULA. 



ter. Both mandibles are narrow and concave within, with a 

 prominent median line ; the palate flat, with two ridges ; the 

 tongue very slender, five-twelfths long, emarginate and papillate 

 at the base, grooved above, its tip slit and slightly fringed. The 

 oesophagus is two and a half inches long, with an average 

 diameter of two-twelfths; the proventriculus five-twelfths long. 

 The stomach is oblongo-elliptical, compressed, its length eight- 

 twelfths, its greatest breadth five and a half twelfths, its mus- 

 cles distinct, the tendons two-twelfths across, the cuticular 

 lining thin and smooth. The intestine is six and a half inches 

 long, of nearly uniform diameter as far as the coeca, its duo- 

 denal portion measuring two-twelfths across. The rectum is 

 an inch long, dilates immediately, and forms a roundish sac 

 at its lower part, half an inch in width. The coeca are cylin- 

 drical, a twelfth and a half in length. 



The nostrils are very small, being only three-fourths of a 

 twelfth in length, direct, open, elliptical, with a narrow oper- 

 culum. The aperture of the eyes is two-twelfths and a half 

 in diameter ; the eyelids with two sub-marginal rows of small 

 rounded feathers. The ear is transversely elliptical, and 

 nearly three-twelfths in its greatest diameter. The feet are 

 of moderate length, very slender ; the 

 tarsus very much compressed, with 

 only the lower scutella distinct ; the 

 first toe with eight, the second with 

 ten, the third with fourteen, the fourth 

 Fig. 156. with fourtceu scutella. The claM^s are 



of moderate length, arched, extremely compressed, that of 

 the hind toe much larger, but curved in the same degree as 

 the rest. 



The plumage is soft and blended. The wings are of ordin- 

 ary length, although their tips are three inches short of the 

 extremity of the tail. The primaries are nine, the first and 

 third equal, the second scarcely larger, the second, third, and 

 fourth slightly cut out on the outer web towards the end ; 

 the outer narrowed and rounded, the inner very broad and 

 obliquely rounded ; of these eight secondaries the outer are 

 rounded and slightly emarginate, the inner three tapering, 



