650 CYGNUS. SWAN. 



Mouth of moderate width. Anterior palate deeply con- 

 cave, with a lateral series of obscure flattened lamellae on 

 each side, not separated by a groove from the slender, little 

 elevated marginal lamella?, a medial row of prominent blunt 

 tubercles, and an intermediate oblique series of flattened 

 tubercles. The tongue is fleshy, thick, with the sides 

 parallel, the base with a dorsal row of conical papillae, a soft 

 large prominence near it ; a deep medial groove, having on 

 each side acute, flat, spreading papilla?, the edges thin, 

 fringed with slender flattened papillae, of which the posterior 

 are large and serrulate, the anterior small ; and under this 

 series a smaller row of filaments extending behind the base 

 of the tongue. (Esophagus extremely long, narrow, dilated 

 a little toward the furcula, then contracted, but with the 

 lower part enlarged. The stomach an extremely developed, 

 oblique, transversely elliptical gizzard, of which the lateral 

 muscles are excessively thick, their tendons large, the lower 

 muscle distinct, with its tendons passing under the others ; 

 the epithelium forming two very thick, considerably concave, 

 smoothish grinding surfaces. The intestine is long, rather 

 narrow, arranged in about sixteen folds ; the coeca long, 

 narrow at the base, then of moderate width and cylindrical ; 

 the cloaca globular. 



The trachea of very numerous, broad, considerably flat- 

 tened rings, in some species curved and entering the sternum 

 before passing into the thorax, in others following the usual 

 course. The inferior larynx laterally compressed, with its 

 last rings united. Appended to the last or semilunar ring 

 on each side is a narrow membrane, terminated by a very 

 slender half-ring, and standing free from the large membrane 

 intervening between the last tracheal and first bronchial 

 rings. The bronchi short, wide, varying in form in the 

 different species. 



Nostrils elliptical, medial, near the ridge, in the fore part 

 of the oblong nasal sinus. Eyes small; eyelids feathered, 

 with bare crenulate margins. Aperture of ear small. Feet 

 short, stout, placed a little behind the centre of equilibrium ; 

 tibia bare for a short space ; tarsus considerably compressed, 

 reticulated with small angular scales. Hind toe very small, 



