BLACK-BILLED EGRET. 461 



mandible with the angle long and extremely narrow, the 

 dorsal line slightly ascending, the sides sloping outwards 

 and concave, the edges sharp, the tip acute. The gape-line 

 straight, commencing under the centre of the eye, at first 

 somewhat sinuate, and toward the end slightly deflected. A 

 large bare space on each side of the head, extending from 

 the base of the bill to a little behind the eye and angle of 

 the mouth. 



The roof of the mouth is slightly concave, with three 

 longitudinal sharp ridges ; the palate convex ; the lower 

 mandible with a groove and ridge on each side, and a central 

 ridge. Tongue very slender, sagittate at the base, tapering 

 to the point, which is acute. The mouth is rather narrow, 

 measuring only seven-and-a-half-twelfths across, but, in con- 

 sequence of the flexibility of the crura of the lower man- 

 dible, is dilatable to an inch and a half. The oesophagus is 

 twenty-eight inches long, an inch and a half in w r idth at the 

 top, about a third down an inch, afterwards an inch and a 

 half, and at the proventriculus two inches and a quarter. 

 The proventricular belt is one inch and three quarters in 

 breadth ; its glandules very numerous, oblong, about a 

 twelfth and a half in length ; at its upper margin are several 

 groups of large mucous crypts having wide apertures. Be- 

 yond the proventriculus the stomach forms a sac two inches 

 in diameter, its muscular coat very thin, being formed of 

 slender muscular fibres converging toward two roundish 

 tendinous spaces ; its inner coat thin, soft, and smooth. 

 Appended to the stomach is a pyloric lobe, ten-twelfths in 

 diameter, internally smooth, its aperture half-an-inch in 

 width. The intestine is nine feet one inch in length, its 

 width varying from three to two-twelfths ; the rectum five 

 inches long, with a coecal appendage at its commencement ; 

 its globular dilatation an inch and three-fourths in diameter. 

 The lobes of the liver are very unequal, the right being 

 three inches and a quarter in length, the left two inches and 

 a half. 



The nostrils are linear, half-an-inch long. The eyes are 

 rather small, the diameter of their aperture four-twelfths 

 and a half. The legs are very long and slender ; the tibia 



