96 
ORNITHOLOGISTS' COMPENDIUM. 
Ochra'ceous-Ru'fous (L. ochra'ceo-ru'fus), n. (Yellow ochre -f- burnt sienna 
-f light red). (Plate V. fig. 5.) 
O'chre- Yellow (L. ochra'ceo-flavus), n. The color of the pigment called 
yellow ochre. (Plate V. fig. 9.) 
Oc'reate (L. ocrea'tus), a. Booted, or having the anterior covering of 
the tarsus undivided for the greater part of its length. 
Odontor'nithes (L.), n. The name of an extinct order or primary group 
of birds, comprising forms which possessed teeth in sockets, and thus, 
as well as in other features, more nearly approaching the reptiles in 
their structure than any living forms. 
Oil Green (L. oleagin'eus), n. A dull light yellowish green. (Schoenf eld's 
yellow-green zinnober.) (Plate X. fig. 21.) 
Olfaclory, n. Pertaining to the sense of smell. 
Oligoto'kous, o. Producing few eggs. 
Oliva'ceous ( °^ ca ' cms ' olivi'nus), n. A greenish brown color, like 
oli '< that of olives. (Sepia -flight zinnober green.) (Plate 
( III. fig. 9.) 
Ol'ive-Buff (L. oliva'ceo-lu'teus), n. (Yellow ochre -j- cobalt blue -f white.) 
(Plate V. fig. 12.) 
01'ive-Gray (L. oliva'ceo-ca'nus), n. (Black -f- white -J- light cadmium.) 
(Plate II. fig. 14.) 
Olive-Green (L. oliva'cco-ri'ridis), n. A peculiar color, common in birds 
(especially the Warblers, and hence sometimes called "warbler- 
green "), produced by the mixture of yellow and gray, resulting in 
a tint somewhat between olive and dull yellowish green. (Light 
zinnober green -}- raw umber.) (Plate X. fig. 18.) 
Olive- Yellow (L. oliva'ceo-fia'vus), n. (Light cadmium -f- black -f 
white.) (Plate VI. fig. 16.) 
Omniv'orous (L. omniv'orus), a. Feeding upon anything eatable; eating 
indiscriminately. 
Ome'goid (L. ome'goideus), a. Resembling in form the Greek capital 
letter Ome'ga, CI. 
Oolog'ical, a. Pertaining to oology. 
OoPogy, n. The science of birds' eggs. 
Opalescence, n. A reflection of pearly tints from a pale or milky 
ground-color. 
Opales'cent (L. opales'cens ; margarita'ceus 1 ), a. Reflecting changeable 
tints from a pale or milky ground-color. 
Opaque' (L. opa'cus), a. In descriptive Ornithology, the opposite of 
metallic, or brilliant. Dull, or without gloss. 
Operculum (L.), n. A lid, or cover, such as the scale overhanging the 
nostrils (operculum naris) of many birds. 
Ophthal'mic (L. ophthal'mkus), a. Pertaining to the eye. 
Op'tic, a. Pertaining to the sight. 
1 Properly, this term means pearly; but as used in descriptions the terms are 
essentially synonymous. 
