*VIII GLOSSARY OF TERMS 



CERE. The bare and sometimes swollen and distinctively coloured skin in 



which the nostrils are situated at the base of the bfll a prominent 



feature in the Hawks. (See fig., p. *xm.) 

 COMPRESSED. Pressed together, i.e. flattened in a horizontal plane laterally 



compressed flattened in a vertical plane. 

 CORNEOUS. Horny, hard. 

 CULMEN. The central longitudinal ridge of the upper mandible. (See 



fig., p. *xvi.) 

 CUNEATE. Wedge-shaped e.g. the two sides of a feather or tail are rapidly 



graduated to a point, the long axis being not greatly in excess of the 



transverse (cf. LANCEOLATE). 

 CUTTING EDGES OF BILL. The more or less sharp lower margins of the upper 



jaw and upper margins of the lower jaw. (See fig., p. *xvi.) 



DEGENERATE FEATHER. One whose structure has been so modified that many 

 of its essential features may be apparently or actually absent. 



DESMOGNATHOUS. Like the Desmognathae, the third suborder of Carinata? 

 in Huxley's Classification. It is based on the fact that in the groups 

 comprised in it (Ducks, Geese and Swans, Flamingo, Storks, Herons, 

 Ibis, Spoonbill, Cormorants, Birds of Prey, Cuckoos, Bee-eater, 

 Hoopoe and Roller, amongst British birds) the vomer is more or less 

 suppressed or absent (cf. /EGITHOGNATHOUS). 



DIASTATAXIC. Arranged separately. Divided. 



DIMORPHISM. A difference in form, and also used generally in ornithology for 

 a difference in colour (strictly dichromatism), constantly exhibited by- 

 different individuals of the same species. Sexual dimorphism is 

 common in birds, but individual dimorphism is rare. 



DISTAL. A part remote from the centre or central line of the body as opposed 

 to a part nearer the centre (PROXIMAL). 



DOWN. The first covering of the young of many birds, but present also 

 beneath the feathers in certain families (Ducks, Geese, etc.) throughout 

 life. (See NEOSSOPTILES and TELEOPTILES. ) 



EGG-TOOTH. The conical horny excrescence situated towards the distal 

 extremity of the culmen in the newly-hatched chick ; it is used to 

 crack the shell at birth, and is shortly afterwards shed. 



EMARGLNATED. Cut out or cut away in a slanting direction. 



ERYTHRISM. The abnormal replacement of other colours, generally green 

 or yellow, by red. 



ETHIOPIAN REGION. The name of one of the six Zoo-geographical Regions 

 of the world, comprising Africa south of the Pahearctic Region and 

 southern Arabia (cf. PAL^ARCTIC and NEARCTIC REGION). 



FILOPLUME. A hair-like feather consisting of calamus and rhachis with but 

 very few radii. 



FESTOONED. Indented or scalloped. 



GAPE. The angle formed by the lower border of the upper jaw and the 



upper border of the lower jaw, when the bill is open. 

 GONYS. The prominent ridge formed by the junction of the two halves of 



the lower jaw towards its tip. Specially marked in the Gulls. (See 



fig., p. *xv.) 



GRADUATED. Of gradually increasing or decreasing length or width. 

 HALLUX. The first digit of the foot (i.e. the great toe). The toe which in 



most orders is the only one that is directed backwards (i.e. hind toe) ; 



very variable in size and in some species absent 



