676 CYGNUS AMERICANUS. 



what depressed form ; the neck extremely long and slender ; 

 the head of moderate size, oblong, compressed. The bill is 

 rather longer than the head, straight, higher than broad at 

 the base, gradually depressed, a little wider toward the end ; 

 upper mandible with the dorsal line, not including the con- 

 cave space beyond the joint, descending and very slightly 

 convex to beyond the nostrils, then slightly concave, and 

 ultimately decurved ; the ridge broad and flat at the base, 

 gradually narrowed, beyond the nostrils convex, the sides 

 nearly erect and somewhat concave at the base, gradually 

 sloping, and becoming more convex ; the margins soft, nearly 

 parallel, but toward the end widening a little ; the unguis 

 large, broadly obovate, convex, thick-edged, and internally 

 grooved. The lower mandible with the intercrural space 

 very long and of moderate width, its membrane bare for 

 more than two-thirds, the crura convex beneath, with their 

 lower outline slightly re-arcuate, the laminated margins in- 

 clinate, the unguis very large, obovato-elliptical, with a wide 

 groove on each side ; the gape-line slightly re-arcuate. 



The upper mandible deeply concave, with a medial pro- 

 minent papillate ridge, and on each side an oblique series of 

 transverse flattened tubercles, a submarginal series of incon- 

 spicuous slender lamellae, and a marginal series of about 

 thirty-five transverse, more or less oblique, slender, little 

 elevated, obtusely terminated lamellae, not projecting beyond 

 the margin. The lower mandible has twenty-two external 

 and about sixty internal lamellae. 



The nostrils are oblong, nearly half an inch in length, 

 direct, medial, near the ridge, in the lower anterior part of 

 the oblong sinus. The eyes are very small, their aperture 

 measuring five-twelfths. That of the ear round, four-twelfths 

 in diameter. The legs are short, very stout, placed a little 

 behind the centre of the body ; the tibia very muscular, bare 

 for nearly an inch and a half; the tarsus short, considerably 

 compressed, reticulated with angular scales, of which the 

 anterior are large and rounded ; the hind toe very diminu- 

 tive, with a slight thickened lower margin ; the middle toe 

 longer than the tarsus ; the outer considerably longer than 

 the inner, and reticulated to the third joint, the inner reticu- 



