HERONS AND ALLIED SPECIES. 401 



rather wide, and capable of being much dilated in conse- 

 quence of the flexibility of the crura of the lower jaw. The 

 palate is convex, anteriorly with two papillate ridges, and a 

 median prominent line which runs to the point of the man- 

 dible. The posterior aperture of the nares is linear. The 

 tongue long, slender, trigonal, tapering, sagittate at the 

 base, with a large pointed papilla on each side, the tip 

 acute. Although there is a large gular sac, the skin on the 

 throat is feathered. The oesophagus is very wide in its 

 whole length, with its walls thin, and its inner coat longi- 

 tudinally plicate ; the proventriculus very wide, its glands 

 forming a broad belt, at the upper margin of which are 

 numerous large mucous crypts in groups. The stomach, a 

 very large rounded sac, of which the muscular coat is ex- 

 tremely thin, and formed of very slender fasciculi, with the 

 inner coat thin, soft, and smooth. Attached to it is a glo- 

 bular pyloric lobe. The intestine is very long and extremely 

 narrow ; at the commencement of the rectum is an oblong 

 small caput coecum, but no lateral coecal appendages ; the 

 cloaca very large and globular. 



The trachea, which is composed of numerous, very thin 

 rings, is considerably flattened and gradually narrowed; the 

 last four rings dimidiate. A pair of cleido-tracheal muscles 

 pass from the thyroid bone to near the middle of the furcula. 

 The lateral muscles, thin and slender at the upper part, 

 become thicker below, and extend over the whole surface 

 before and behind. A slip from them, on each side, extends 

 to the last half-ring. The bronchi are wide, of numerous 

 half-rings, their membrane large. 



The eyes are of moderate size, generally surrounded with 

 a bare space. The nostrils linear, in the small nasal mem- 

 brane, from which a groove extends anteriorly, but in some 

 genera is obsolete. The aperture of the ear is small and 

 roundish. 



The tibiae are very long, and generally bare to a great 

 extent ; the tarsi long and rather stout ; the toes four, of 

 which the first is slender, and placed nearly on a level with 

 the anterior, which are long and rather slender, scutellate 

 above, flattened beneath, and connected by basal membranes. 



c c 



