578 STRUCTURAL CHARACTERS 



middle ; feathering of forehead extending forward to a point between the nostrils.; 

 tail of fourteen feathers. (Vol. iv. p. 544.) 



(p) Genus Somateria. Beak long ; feathers of the forehead extending forwards on to 

 the culmen to form an /?z-shaped extension, in which the median lobe may be 

 of great length ; tail of fourteen feathers. (Vol. iv. pp. 256, 544.) 



(q) Genus Oidemia. Beak more or less swollen at the base ; nostrils in the middle of 

 a line drawn from the tip to the gape ; lamellae large and widely spaced, outer as 

 long as the middle toe and much longer than the tarso-metatarsus ; hallux with 

 a large lobe ; syrinx without bullse. (Vol. iv. pp. 259, 545.) 



(r) Genus Mergus. Beak subcylindrical, with strong serrations along the tomium or 

 cutting edge of the lower jaw ; hind-toe with a large lobe. (Vol. iv. pp. 286, 546.) 



VIII 



ORDER : CICONIIFORMES 



Palate desmognathous ; basipterygoid processes wanting ; spina interna wanting ; caeca 

 vestigial; single pair of tracheal muscles : oil-gland tufted ; wing diastataxic; young nidicolous. 



SUBORDER : AEDE^E 



Beak long and pointed; hypo tarsus complicated, with long cervical apteria; claw of middle 

 toe pectinated ; nostrils holorhinal ; hinder border of sternum with a single pair of notches ; 

 hallux on the same plane as the front toes. 



1. FAMILY ARDEID.S HERONS. 



With large powder-down patches ; eleven primaries ; nineteen to twenty cervical vertebrae. 



(a) Genus Ardea. Twelve rectrices ; tarso-metatarsus longer than the middle toe and 



claw ; claw of hallux curved, not half as long as the hallux itself; edges of beak 

 serrated. (Vol. iv. pp. 326, 547.) 



(b) Genus Phoyx. Tarso-metatarsus less than the length of the middle toe and claw ; 



twelve rectrices ; claw of hallux long, nearly straight. 



(c) Genus Herodias. Edges of beak not serrated ; culmen not exceeding the length of 



the middle toe and claw, with a long dorsal train of plumes. 



(d) Genus Garzetta. Culmen exceeding the length of the middle toe and claw ; tarso- 



metatarsus longer than the beak, with a long dorsal train of plumes. (Vol. iv. p. 548.) 



(e) Genus Nycticorax. Beak laterally compressed, equal to the tarso-metatarsus in 



length ; tail short, of twelve feathers ; tarso-metatarsus longer than the middle toe, 



with hexagonal scutellse in front. (Vol. iv. p. 549.) 

 (/) Genus Ardeola. Beak long, serrated near the tip ; equal in length to the middle 



toe and claw ; tail of twelve feathers ; with well-developed dorsal plumes and a 



pendent nuchal crest. (Vol. iv. p. 548.) 

 (g) Genus Ixobrychus. Beak serrated, slender, longer than the head ; tail of ten 



feathers ; tarso-metatarsus anteriorly scutellated, as long as the middle toe and 



claw ; back of neck down-covered ; lateral neck feathers much elongated. 

 (h) Genus Botaurus. Beak longer than the head, serrated ; tail of ten feathers ; middle 



toe and claw much longer than the tarso-metatarsus; claw of hallux very long, 



nearly as long as the hallux ; lateral neck feathers much elongated ; back of the 



neck down-clad only. (Vol. iv. pp. 330, 550.) 



