BURROW SHIELDUCK. 23 



and coverts, wJdcJt are black; the outer secondaries green, 

 some of the inner externally red, and the lower tail-coverts 

 brownish -ijcllow. Female smaller, similarly though less 

 brightly coloured, bat without the fleshy knob on the forehead. 



Male in Winter. — This species, the largest, and one of 

 the most beautiful of our native Ducks, has by some been 

 considered as belonging to the Anserine rather than the 

 Anatine family ; but the form of its bill, the narrow incurved 

 unguis of the upper mandible, the delicate lamellae, the ex- 

 pansion of the lower part of the trachea, and other characters? 

 clearly evince its connection with the latter group. It is not 

 much inferior in size to the Black-faced Bernicle Goose, and 

 has the body large, full, somewhat lengthened, and well- 

 balanced on the legs ; the neck rather long, and narrowed 

 above ; the head moderate, oblong, compressed, and rounded. 



The bill is about the length of the head, much higher 

 than broad at the base, gradually depressed, becoming a little 

 wider toward the end, considerably rearcuate. The angle at 

 the base of the ridge is occupied by a fleshy coloured tubercle, 

 which is anteriorly carinate ; the lateral sinuses broadly 

 rounded, the ridge broad at the base, gradually narrowed, 

 the dorsal line descending to beyond the nostrils, then a little 

 concave, the sides erect at the base, gradually more sloping, 

 the edges membranous, the unguis oblong, small, much 

 curved and abrupt at the end ; the lamellae not projecting ; 

 the nasal sinus moderate, elliptical, sub-basal, close to the 

 ridge ; the lower mandible considerably rearcuate, with the 

 intercrural space very long and narrow, the unguis somewhat 

 elliptical, but with the sides nearly parallel ; the tip rounded. 



The mouth is rather narrow, measuring eight-twelfths 

 across. The posterior aperture of the nares lanceolate, mar- 

 gined with acicular papilla?. The anterior palate concave 

 and recurved, with a medial soft ridge, on the basal half of 

 which are some compressed papillae, toward the end numerous 

 minute, oblique striae, and on each side about seventy-five 

 transverse, thin, elevated lamellae, of which the anterior are 

 larger and more distant, the outer ends of all not thickened, 

 nor at all resembling those of the Geese, but many of them 



