OCEL´LUS, _n._ (Literally “little eye.”) Distinct rounded spot of color,
like the “eyes” of a peacock’s tail.
OCH´REY, OCH´REOUS, _a._ Color of yellow ochre.
OC´REATE, _a._ Booted. See BOOT and CALIGULA.
OC´ULO-MO´TOR, _n._ A nerve of the eye-muscles.
OC´ULUS, _n._ Eye. (The adjective _ocular_ being applied chiefly to
processes and results of sight, much like _visual_, rather than to
physical attributes, the word _orbital_ is used for the latter instead.)
ODON´TOID (_process_), _a._ A part of the axis (second cervical
vertebra) is so called.
ŒSOPH´AGUS, _n._ Gullet; tube conveying food from mouth to stomach.
OLEC´RANON, _n._ Upper back part of the ulna, not prominent in birds.
OLFAC´TORY, _a._ Pertaining to the sense of smell.
OLIGOMY´OID, _a._ Having few or imperfect syringeal muscles among
_Passeres_.
OLIGOTO´KOUS, _a._ Producing few young.
OLIVA´CEOUS, _a._ Of a mixed green and brown color.
OMNIV´OROUS, _a._ Eating anything; feeding indiscriminately.
O´MOPLATE, _n._ Shoulder-blade. (_Omo-_, in composition, is a prefix
referring to the shoulder.)
OM´PHALOS, _n._ Same as _umbilicus_, navel.
OÖLOG´ICAL, _a._ Pertaining to oölogy.
OÖL´OGY, _n._ Science of birds’ eggs.
OPER´CULUM, _n._ Lid or cover; flap. The nasal scale, or roofing of the
external nostrils, is the _operculum naris_.
OPHTHAL´MIC, _a._ Pertaining to the eye. _Ophthalmic_ region is
equivalent to orbital region.
OP´TIC, _a._ Pertaining to the eye, or to the sight. The _optic_ nerve
issues from the brain and spreads into the retina.
O´RAL, _a._ Pertaining to the mouth.
ORBIC´ULAR, _a._ Circular.
OR´BIT, _n._ Eye-socket. Also, synonymous with _orbita_.
OR´BITA, _n._ Circumorbital region taken immediately around the
eye-opening. (41.)
OR´BITAL, _a._ Pertaining to the orbit.
ORBI´TO-SPHE´NOID, _n._ Part of the sphenoid bone, forming a portion of
the orbit.
OR´DER, OR´DO, _n._ In classification, a group pl. _ordines_, between
family and class.
OR´DINAL, _a._ Having the taxonomic rank or value of an order.
OR´GAN, _n._ Any individual part, or system of parts, of the body having
a specific physiological function, considered with reference to its
action, processes, or results. Eye, _organ_ of sight; wing, _organ_ of
flight; stomach, liver, _organs_ of digestion; muscles collectively,
_organs_ of locomotion.
OR´GANISM, _n._ Any living body capable of separate existence.
OR´GASM, _n._ Immoderate excitement; said chiefly of sexual excitement,
of which the _orgasm_ is the height. Erethism.
ORNITH´IC, _a._ Pertaining to birds.
ORNITHOCOP´ROLITE, _n._ Fossil bird-dung.
ORNITHOL´OGY, _n._ Science of birds.
ORNITHOT´OMY, _n._ Anatomy of birds.
OS, _n._; gen. _oris_; pl. _ora_. Mouth. _Cavum oris_, cavity of the
mouth.
OS, _n._; gen. _ossis_; pl. _ossa_. Bone. Many or most names of
individual bones are adjectives, used substantively, _os_ or _bone_
being understood; as, _hyoid_ or _hyoides_, _hyoid_ (bone) or (_os_)
_hyoides_, etc. The _quadrate bone_ or _os quadratum_ is, as to its
physical characters and office, not found in animals above birds; it
hinges the lower jaw, pterygoid, and malar bones to the rest of the
skull. It is regarded as the homologue of the mammalian _incus_ by some,
by others as probably homologous with the mammalian _malleus_.
OS´CINE, _a._ Musical; capable of singing.
OS´CINES, _n. pl._ A group of singing-birds, possessing a complex vocal
organ of numerous syringeal muscles, conferring musical ability. These
are regarded as the highest or most perfectly developed of their class.
OS´SEOUS, _a._ Bony.
OS´SICLE, _n._ A small bone.
OSSIF´IC, _a._ Bony; rather, having power to ossify.
OS´SIFIED, _a._ Become bony; united by bone.
OS´SIFY. To form bone; to change into bone.
OSTEOLOG´ICAL, _a._ Pertaining to osteology.
OSTEOL´OGY, _n._ A description of bones. Also used to denote the osseous
system, as myology, neurology, splanchnology, likewise are for their
respective systems.
OS´TIUM, _n._ Doorway; entrance.
O´TIC, _a._ Pertaining to the ear.
O´TOCRANE, _n._ “Skull of the ear”; cavity containing essential organs
of hearing.
OUTER COVERING. (142.) See INDUMENTUM and PTILOSIS.
OUTER WEB (of a feather). (150.) See POGONIUM EXTERNUM.
O´VAL, O´VATE, O´VOID, OVOID´AL, _a._ Egg-shaped; in a general sense,
oblong and curvilinear. Distinctions which may subsist between these
words are practically ignored among oölogical writers, who use them
interchangeably for the oblong curvilinear shape when the curve is
unequal at the opposite ends; the terms _elliptical_, _ellipsoidal_,
being generally used to denote a curve equal at both ends. The
transverse contour-line of an egg being always circular, the descriptive
terms refer to the lengthwise contour, considered either as of a surface
or a solid.
OVA´RIUM, _n._; pl. _ovaria_, O´VARY, _n._; pl. _ovaries_, Organ or
tissue in which eggs originate; they subsequently acquire albuminous
deposit, and, in birds, a calcareous shell, in the oviduct.
O´VIDUCT, _n._ Tube conveying eggs from ovary to cloaca.
OVIP´AROUS, _a._ Producing eggs which are developed after exclusion from
the body. Opposed to _viviparous_.
OVIPOSI´TION, _n._ Act of laying eggs.
O´VISAC, _n._ Ovarian cavity in which an egg originates. Graafian
vesicle.
OVULA´TION, _n._ Formation of eggs in, and discharge from, the ovary.
O´VUM, _n._; pl. _ova_. Egg. Sometimes synonymous with _embryo_.