GLOSSARY OF TECHNICAL TERMS. 
75 
Dimorph'ic, a. Existing in two forms, as some species of insects. 
Dimorphism, n. The state of existing in two forms. (The nearest 
approach to dimorphism among birds is the state of dichromatism, 
which see.) 
Disc, ) Set of radiating feathers surrounding the eye in some birds, 
Disk, ) n ' especially the Owls. 
Dis'tal, a. Toward or at the extremity. (Opposite of proximal, or toward 
the base.) 
Dis'tichous (L. dis'tichus), a. Two-rowed, as the webs of a feather. 
Ditok'ous, a. Producing but two eggs for each clutch, as the Pigeons 
(Columbidce), Humming-birds (Trochilidce), and a few other groups. 
Diurnal (L. diurna'lis), a. Pertaining to the daytime. Among birds, 
those which are active during the daytime and repose at night. 
(Many diurnal birds, however, are nocturnal in their migrations). 
Divar'icate (L. divarica'tus), a. Spreading or curving apart. 
Dor'sal (L. dorsa'lis), a. Pertaining to the back. 
Dor'sum (L), n. The back. (Plate XI.) 
Double emar inate ^ biemargi?ia'tus) , a. A doubly emarginate tail 
_ ~ ' < has the middle and lateral feathers slightly 
y \ longer than the intervening ones. 
Double-forked \ tyf urca ' tus )y a - A doubly forked tail has the middle 
Doubly forked' ) auc ^ ^ atera ^ feathers decidedly longer than those 
' ' between. 
Double-rounded { °i r °t un da'tus) > a - A doubly rounded tail has the 
Doubly rounded' ) middle and lateral feathers shorter than those 
' ' between. 
Down (L. floc'cus), n. Small soft decomposed feathers, which clothe the 
nestlings of many birds, and which also grow between and under- 
neath the true feathers in the adults of many others, especially the 
various kinds of water-fowl. 
Down'y (L. pubes'cens), a. Pertaining to or having the nature of down, 
or clad with down. 
Drab, ??. A brownish gray color. (Black -f- white-}- raw umber.) (Plate 
III. fig. 18.) 
Drab-Gray, n. (Black + white + burnt umber.) (Plate II. fig. 13.) 
Dragon's-blood Red, n. A rich brownish red color, of a peculiar tint. 
(The pigment called dragon's blood is made from the inspissated juice 
of certain tropical plants, particularly the Calamus draco and Dracaena 
draco.) (Light red -f- madder-brown.) (Plate IV. fig. 8.) 
Dusk'y (L. obscu'rus ; nigres'cens ; nigricans), n. or a. A dark color of 
more or less indefinite or neutral tint ; of a dark, indefinite color. 
Dysporomorph'ae (L. ), n. The Huxleyan name (meaning gannet-formed) 
for the Steganopodes. 
