The Female is considerably smaller, but otherwise similar.
Length to end of tail 17 inches, to end of wings 17, to end of claws 21 3/4; extent of wings 25. Weight 6 1/4 oz.
Young fully fledged. Plate CCCXXXIII.
The bill dull greyish-green, the lower mandible lighter: bare space around the eye greenish-blue, with the exception of a streak of yellow at the upper part. Iris yellow. Feet greenish-yellow, duller than in the adult. The hind neck light brownish-red, the fore part of the neck and all the under parts white, longitudinally streaked with brownish-red, some of the long feathers on the sides of the neck also white. At this age there are no elongated feathers on the back, which is greenish-blue, as well as the scapulars, and tail-feathers. Wing as in the adult, but the smaller feathers on its anterior part more red, the coverts with a small triangular tip of white, and the quills narrowly tipped and margined with the same.
Length to end of tail 17 1/2 inches, to end of wings 17, to end of claws 23; extent of wings 25. Weight 6 1/2 oz.
The roof of the mouth is anteriorly a little concave, with a median prominent line; the palate convex; the lower jaw with a kind of joint about an inch from the base, its intercrural membrane or skin very extensile. The tongue is 1 7/12 inch long, very slender, trigonal, emarginate at the base, with a groove along the middle, and pointed. Posterior apertures of nares linear, 1/2 inch long. Œsophagus, a, b c, 10 inches long, its walls delicate, its diameter at the upper part 1 1/4 inch, gradually contracting to 1/2 inch at its entrance into the thorax. The lobes of the liver unequal, the right 1 inch 5 twelfths long, the left 11 twelfths; the gall-bladder large, 7 twelfths long. The stomach, c, d, is membranous, of an oblong form, 9 twelfths long, 10 twelfths in breadth; its tendons elliptical, twelfths by 3 twelfths. The proventriculus, c c, 9 twelfths long, with a complete belt of oblong glandules. There is a small roundish pyloric lobe e. Intestine, f, g, 2 feet 11 inches long, its diameter uniform, 1 twelfth, or about the thickness of a crow’s quill. Rectum enlarged to 3 twelfths, and 3 1/4 inches long, its cœcal extremity rounded, and only one-twelfth long.
The trachea is 7 1/4 inches long, of nearly uniform diameter, averaging 2 twelfths; the rings 160, nearly circular and ossified. The bronchial half-rings about 18. The lateral muscles are very inconspicuous; sterno-tracheals; and a pair of inferior laryngeal, going to the first bronchial rings.
The Herons generally differ from the other Grallæ in having the œsophagus much wider and similar to that of the fish-eating palmipedes; the stomach in a manner membranous, like that of the rapacious land-birds, without lateral muscles or strung epithelium; the intestine extremely slender, and the anterior extremity of the large intestine or rectum furnished with a single cœcum, in place of two, as in almost all other birds.