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GLOSSARY. 



DicuitOMATic, a. In descriptive orni- 

 thology, a species is said to be dichro- 

 matic when it exists in two distinct 

 pinmages which are entirely inde- 

 pendent of sex, age or season. These 

 distinct plumages were formerly, in 

 the case of most dichromatic birds, 

 supposed to represent distinct species, 

 and the nature of their real relation- 

 ship is a comparatively recent discov- 

 ery. Familiar examples of dichro- 

 matism are the rufous and gray forms 

 of the little Screech Owl and the white 

 and bluish or dusky forms of some 

 Herons (as Ardea occidentalis and Di- 

 ckromanassa rufa). 



DiCHROMATisM, n. The state of exist- 

 ing in two distinct pliases of colora- 

 tion, which are wholly independent of 

 the usual causes of color differences 

 (as sex, age and season). Dichromat- 

 ism among birds is somewhat analo- 

 gous to dtmorphism in insects. 



DiDACTYLE, \a. Two toed, as the 



DiDACTYLOUS, [ Ostrich. 



DiGiTiGKADE, a. Walking on the toes. 

 (Applicable to most birds.) 



DiMoKPHic, a. Existing in two forms, 

 as some species of insects. 



Dimorphism, n. The state of existing 

 in two forms. ( The nearest approach 

 to dlmoriihism among birds is the 

 state of dichromatism, which see.) 



-p. i n. Set of radiating feathers 

 ISC, ) surrounding the eye in some 



■^^^^' ( birds, especially the Owls. 



Distal, a. Toward or at the extrem- 

 ity. (Opposite of proximal, or toward 

 the base.) 



j a. Two rowed, as the 

 '''''' \ webs of a feather. 

 ' a. P r o d u c i n g l)ut two 

 eggs for each clutch, as 

 the Pigeons, Humming- 

 birds, and a few other 



Distichous 



DiTOKOUS, ■ 



DiVABXCATE, 



groups. 



j a. Spreading or curv- 

 ' ( ing apart. 

 Dorsal, a. Pertaining to the back. 

 Dorsum, n. The back. 



[ a, A doubly emargin- 

 ate tail has the 



Double 



emarginate, 

 Doubly 



emarginate, 



middle and lateral 

 feathers slightly 

 longer than the in- 

 tervening ones. 

 a. A doubly forked tail has 

 the middle and lateral 

 feathers decidedly long- 

 er than those between. 



Double (a. Kdonbly rounded tail 



ROUNDED, J has the middle and lat- 



DouBLY' I eral feathers shorter 



ROUNDED, [ than those between. 



Down, /i. Small, soft, decomposed feath- 

 ers, which clothe ihe nestlings of many 

 birds, and which also grow between 

 and uuderneatli the true feathers in 

 the adults of many others, especially 

 the various kinds of water fowl. 



Downy, a. Pertaining to or having the 

 nature of down, or clad witli down. 



E. 



Ear Coverts, n. The usually well- 

 defined tract of feathers overlying the 

 ears of most birds. The ear coverts 

 (or auriculars, as they are usually 

 termed in descriptions) are bounded 

 above by the backward extension of 

 the supercilum, or lateral portion of 

 the crown, posteriorly by the occiput 

 and nape, below by the malar region or 

 "cheeks," and anteriorly by tlie sub- 

 orbital region. ( Same as auriculars.) 

 Eared, a. Decorated with tufts of 

 feathers, distinguished by length or 

 color, which by their appearance sug- 

 gest the external ears of mannnals. 

 Ear Tufts, n. Erectile tufts of elong- 

 ated feathers springing from each side 

 of the crown or forehead, and present- 

 ing a close superficial resemblance to 

 the external ears of many mammalia. 

 They are especially characteristic of 

 certain Owls (Strigidce). 

 Economy, n. Physiological disposition. 

 Ecto (in composition). Outer; asecto- 



zoon, an external parasite. 

 Edge of Wing, ?i. The anterior bor- 

 der of the wing, from the armpit to 

 the base of the outer primary. 



' a. An emarginate 

 tail has the middle 

 feather shortest, 

 the rest succes- 

 sively a little 

 longer; hence, an 

 EiMARGiNATE, J emarginate tail is 

 Emarginated, 1 very slightly 

 forked. An emar- 

 ginate quill has 

 the web suddenly 

 narrowed by an 

 abrupt cutting 

 away of the edges. 

 Embry'O, 77. In birds, the young before 



leaving the egg. 

 Ensate, Ensiform, a. Sword shaped. 



