498 SYSTEMATIC SYNOPSIS — EAPTOBES— STBIGES. 



Physiognomy not peculiar; no great lateral expansion of the cranium or thickening of ite walls 

 witli diploij; eyes looking sideways; no facial disc or only an imperfect one; base of bill not 

 hidden by appressed feathers. Nostrils wholly in tbe cere. Tomia usually toothed or lobed. 

 No external ear-conch. Outer toe not shorter tban inner, and rarely versatile. Basal joint of 

 middle toe longer than the next. Feet with rare exceptions mostly or entirely naked of feathers, 

 Bcutellate or reticulate, or both ; toes always bare and scaly. Sternum commonly single- 

 notched or -fenestrate on each side, sometimes entire. Oil-gland tufted. Plumage compact, 

 usually aftershafted ; flight audible. Ambieiis present. Diurnal .... ACCIPITEES. 



Outer toe not reversible, and plumage usually aftershafted Falcokid/E. 



Outer toe reversible, and plumage without aftershafts Pandionid.e. 



Physiognomy pecuhar by reason of great lateral expansion, lengthwise contraction and diploic 

 thickening of the often unsymmetrical cranium ; eyes looking forward, surrounded with a radi- 

 ated disc of modified leathers, in front appressed, antrorse, hiding base of bill. Nostrils usually 

 at edge ol the cere. Tomia never lobed or toothed. A Urge external ear-conch often devel- 

 oped. Outer toe completely versatile, shorter than inner toe. Basal joint of middle toe not 

 longer than second, much shorter than the penultimate one. Feet usually feathery or bristly 

 to or on the toes. Oil gland nude. Plumage without aftershafts, soft and lax ; flight noiseless. 

 Ambiens absent. Nocturnal STRIGES. 



Sternum entire behind, with central emargination ; furculum anchylosed. Middle claw- 

 pectinate. Facial disc complete, triangular Aldcokida:. 



Sternum double-notched or fenestrate; fujculum free. Middle claw not pectinate. Facial 

 disc circular when complete Strigidje. 



6. Suborder STRIGES : Nocturnal Birds of Prey. 



Head very large, and especially broad from side to side, but shortened lengthwise, th& 

 "face "thus formed further defined by a more or less complete " ruff," or circlet of radiating 

 feathers of peculiar texture, on each side. Eyes very large, looking more or less directly for- 

 ward, set in a circlet of radiating bristly feathers, and overarched by a superciliary shield. 

 External ears extremely large, often provided with an operculum or movable flap, presenting 

 the nearest approach, among birds, to the ear-conch of mammals. Bill shaped much as in 

 ordinary Accipitres, but thickly beset at base with close-pressed antrorse bristly feathers, 

 and never toothed. Nostrils large, commonly opening at the edge of the cere rather than 

 entirely in its substance. Hallux of average length, not obviously elevated in any case ; outer 

 toe more or less perfectly versatile (but never permanently reversed), and shorter than the 

 inner toe ; its first three joints very short, altogether not as long as the succeeding one ; basal 

 joint of middle toe not longer than the next. Claws all very long, much curved and extremely 

 sharp, that of the middle toe pectinate in some species. As a rule, the tarsi are more or less 

 completely feathered, and the whole foot is often thus covered. Among numerous osteological 

 characters may be mentioned the frequent want of symmetry of the skull, wide separation of the 

 inner and outer tablets of the brain-case by intervention of spongy diploe, the spongy maxillo- 

 palatines and lacrymals, which latter long persist distinct ; the basipterygoid processes ; the 

 manubriated and commonly 4-notched (if not entire) sternum ; a peculiar structure of the tarso- 

 metatarsus ; a particular arrangement of the bones about the shoulder-joint, and the weakness 

 of the furculum when not anchylosed with the sternum. The gullet is capacious but not 

 dilated into a special crop ; the gizzard is only moderately muscular ; the intestines are short 

 and wide ; the coeca are extremely long and club-shaped. The syrinx has one pair of intrinsic 

 muscles. The oil-gland is nude. The ambiens is absent. The feathers have no aftershaft, 

 and the general plumage is very soft and blended. 



The Nocturnal Birds of Prey will be immediately recognized by their peculiar physiognomy,, 

 independently of the technical characters that mark them as a natural, sharply-defined group. 

 They are highly monomorphic, without extremes of ahen-ant form; but the ease with which 

 they are collectively defined is a measure of the difficulty of their rigid subdivision, which is- 

 not yet satisfactorily determined. Too much stress has been laid upon the trivial, although 

 evident, circumstance of presence or absence of the peculiar " horns " that many species possess. 



