AS MEANS OF IDENTIFICATION 577 



rated edges covered with a thin skin, and terminating in a " nail " ; tongue large, fleshy, 

 and laterally bordered with lamelku ; toes webbed. 



(a) Genus Anser. Tarso-metatarsus covered in front as well as at the back and sides 

 with hexagonal reticulations ; legs relatively long ; lores feathered ; serrations on 

 the cutting edge of the upper jaw projecting beyond the toinium, which is sinuated 

 or concave. (Vol. iv. p. 151.) 



(6) Genus Branta. Differs from Anser only in that the serrations of the upper jaw 

 are concealed save only at the gape; tomium straight. (Vol. iv. p. 157.) 



(c) Genus Cyynus. Lores naked ; front of the tarso-metatarsus reticulated ; neck very 



long; legs short; hallux without a lobe. (Vol. iv. p. 171.) 



(d) Genus Tadorna. Beak conspicuously recurved ; hind-toe without a lobe ; tarso- 

 metatarsus nearly as long as the middle toe and claw ; wrist of the wing with a 

 more or less conspicuous knob or incipient spur, but covered with feathers ; syrinx 

 with a double bulb ; coloration conspicuous ; sexes alike. (Vol. iv. pp. 189, 540.) 



(e) Genus Anas. Beak as long as the head, more or less depressed dorso-ventrally ; 

 lamella along the edges of both upper and under jaws well marked ; tail of 

 eighteen feathers, of which the four central in the male are recurved. (Vol. iv. 

 pp. 191, 540.) 



(/) Genus Spatula. Beak much longer than the head, conspicuously laterally 

 expanded at the tip; lamellie very long; legs very short; tail of fourteen 

 feathers. (Vol. iv. p. 196.) 



(g) Genus Dafila. Beak as long as the head ; lamellae not conspicuously developed ; 

 inner secondaries and scapulars elongated and acuminate; tail of sixteen 

 feathers, long and pointed ; neck very long and slender. (Vol. iv. p. 199.) 



(h) Genus Nettion. 1 Beak narrow ; lamella; not projecting beyond the cutting edges, 

 nearly as long as the head ; inner secondaries and scapulars elongated ; tail of 

 sixteen feathers, short and rounded. (Vol. iv. pp. 202, 540.) 



(i) Genus Mareca. Beak conspicuously shorter than the head, tapering towards the 

 tip ; lamella? of upper jaw projecting beyond the cutting edges ; tail of sixteen 

 feathers, short and pointed ; hallux with a small lobe. (Vol. iv. pp. 207, 541.) 



(k) Genus Nettion. Beak long, conspicuously recurved, not expanded at the tip ; 

 loral feathering with a straight or slightly concave anterior outline ; nail more 

 than one-third as wide as the transverse diameter of the middle of the beak ; 

 hallux with a large lobe. (Vol. iv. pp. 202, 540.) 



(1) Genus Fuligula. Beak relatively short, more or less markedly expanded towards 

 the tip ; loral feathering with a conspicuously convex anterior outline ; nail less 

 than one-third as wide as the transverse diameter of the middle of the beak. 

 (Vol. iv. pp. 241, 542.) 



(m) Genus Clangula. Beak much shorter than the head ; lamellae concealed by the 

 overhanging edge of the upper jaw ; nostrils nearer the tip of the beak than to 

 the base ; tail of sixteen feathers ; hallux with a large lobe. (Vol. iv. pp. 250, 543.) 



(n) Genus Harelda. Beak shorter than the head, tapering towards the tip, and with 

 the tomium of the upper jaw rising towards the nail in a conspicuously sudden 

 curve ; lamellae projecting beyond the tomium along the proximal half of the upper 

 jaw ; nostrils near the base of the beak ; scapulars much elongated and lanceolate 

 in the male ; tail of fourteen feathers, the central pair much elongated in the 

 male ; hallux small, with a large lobe. (Vol. iv. p. 253.) 



(o) Genus Histrionica (Cosmonetta). Beak short, tapering towards the tip; lamellae 

 concealed; tomium nearly straight; nostrils nearer the base of the beak than its 

 1 The genus Querquedula must be merged in that of Nettion. 



