Part 66

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_.

P.

PAB´ULUM, _n._ Food; nourishment; aliment.

PADS. (123.) See TYLARI.

PALÆARC´TIC, _a._ Indigenous to the northern parts of the Eastern Hemisphere.

PALÆOGÆ´AN, _a._ Indigenous to the Eastern Hemisphere, or “Old World.”

PALÆORNITHOL´OGY, _n._ Science of fossil birds.

PAL´AMA, _n._ Webbing between the toes. (138.)

PAL´ATAL, PAL´ATINE, _a._ Pertaining to the palate; _palatine _ is said especially of certain bones.

PAL´ATE, _n._ Roof of mouth.

PAL´ATUM, _n._ The palate.

PA´LEA, _n._ Fleshy pendulous skin of the chin or throat; dewlap.

PAL´LIUM, _n._ Same as STRAGULUM (which see).

PAL´MAR, _a._ Pertaining to the under surface of the pinion.

PAL´MATE, PALMA´TED, PAL´MIPED, _a._ Web-footed; having the anterior toes full-webbed. Compare SEMIPALMATE and TOTIPALMATE.

PAL´MATE FOOT. (139.)

PAL´PEBRA, _n._ Eyelid.

PAL´PEBRAL, _a._ Pertaining to the eyelids.

PAL´PEBRATE, _a._ Having eyelids.

PALU´DICOLE, _a._ Marsh-inhabiting.

PAN´CREAS, _n._ A lobulated gland near the stomach, the secretion of which poured into the duodenum aids digestion by making an emulsion of fat.

PANCREAT´IC, _a._ Pertaining to the pancreas; as, _pancreatic_ fluid.

PAPIL´LA, _n._ Small fleshy nipple-like prominence.

PAP´ILLATE, PAP´ILLOSE, _a._ Having _papillæ_.

PAP´ULÆ, _n. pl._ Pimples.

PAP´ULOUS, _a._ Pimply.

PARADAC´TYLUM, _n._ Side of the toes, in any way distinguished from top or sole. (119.) (Little used.)

PARAGNATH´OUS, _a._ Having both mandibles of equal length, their tips meeting.

PARAPOPH´YSIS, _n._ Certain lateral process of a vertebra.

PARAP´TERUM, _n._ Of uncertain meaning, but has been applied to the scapular region or its feathers. (Little used.)

PARASIT´IC, _a._ Habitually making use of other birds’ nests.

PARATAR´SIUM, _n._ Side of the tarsus, in any way distinguished. (105.) (Little used.)

PARATO´NUM, _n._ Side of upper mandible when distinguished from the culmen. (Little used.)

PARAUCHE´NIUM, _n._ Side of neck. (54.) (Little used.)

PAREN´CHYMA, _n._ Essential substance of a _viscus_.

PARI´ETAL (_bones_), _a._ for _n._ Expanded bones forming part of the cranium.

PARI´ETES, _n._ Wall.

PAROCCIP´ITAL, _a._ for _n._ Certain lateral elements of the occipital bone.

PAROT´IC, _a._ About the ear. (45.)

PAROT´ID, _a._ or _n._ Pertaining to the ear. _Especially_, a salivary gland situate near the ear.

PAS´SERES, _n. pl._ A group of birds including sparrows and all the higher birds.

PAS´SERINE, _a._ Sparrow-like. Belonging to the group of _Passeres_.

PATEL´LA, _n._ Knee-pan; knee-cap. Sesamoid bone of knee-joint.

PAT´ENT, _a._ Open.

PATHOL´OGY, _n._ Physiology of disease.

PEC´TEN, _n._ Same as MARSUPIUM (which see).

PEC´TINATE, PEC´TINATED, _a._ Having tooth-like projections, like those of a comb.

PECTINA´TION, _n._ Comb-like toothing.

PEC´TORAL, _a._ Pertaining to the breast. The _pectoral_ muscles of birds, three in number, are the principal ones in point of bulk in most birds; they move the wing as a whole.

PEC´TUS, _n._ Breast. (62.) Anterior portion of lower part of trunk, between jugulum and abdomen; properly, the region overlying and containing the breast-bone, but generally restricted to the more forward _swelling_ portion of such region.

PE´DES, _n._; pl. of _pes_. Feet. (96.) Leg beyond the end of the tibia.

PED´ICEL, _n._ Narrow foot-stalk or stem by which an organ is attached. Same as _peduncle_.

PELAG´IC, _a._ Frequenting the high seas.

PEL´LICLE, _n._ Any very delicate membrane.

PEL´MA, _n._ The track; entire lower surface of the toes. (114.)

PEL´VIC, _a._ Pertaining to the pelvis.

PEL´VIS, _n._ Cavity of the body formed by the _ossa innominata_, _sacrum_, and _coccyx_; also, these bones collectively.

PE´NIAL, _a._ Pertaining to the penis.

PENICIL´LATE, _a._ Brushy-tipped.

PE´NIS, _n._ The male intromittent organ.

PEN´NA, _n._ A feather. Generally a contour-feather (_pluma_), as distinguished from a down-feather (_plumula_); _particularly_, a large stiff feather of the wing or tail, one of the _remiges_ or _rectrices_.

PENNA´CEOUS, _a._ Denoting a perfect feather complete in all the parts a feather can have; distinguished from _plumulaceous_.

PEN´NIFORM, _a._ Noting a muscle whose fibres are arranged alongside of a central tendon, like the web of a feather.

PER´FORATE, _a._ Pierced through. (Said especially of the nostrils when without a _septum_.)

PERICAR´DIUM, _n._ Bag holding the heart.

PERICRA´NIUM, _n._ Soft parts enclosing the skull; especially the periosteum of the bones.

PERIOS´TEUM, _n._ Membranous investment of bone.

PERIPHERAL PARTS, _n. pl._ Superficial, as opposed to interior, parts.

PERIPH´ERY, _n._ Superficies; contour.

PERISTAL´TIC, _a._ Denoting the peculiar motion of the intestines by which their contents are urged onward; the _peristole_.

PERITONE´UM, _n._ Thin smooth serous membrane lining the belly, and investing most of the contained organs.

PERONE´AL, _a._ Pertaining to the fibula.

PERONE´US, _a._ for _n._ Name of a fibular muscle.

PER´VIOUS, _a._ Open. Used synonymously with _perforate_ in respect of the nostrils, but better restricted to the opposite of impervious or closed (as to an _external_ opening).

PES, _n._; pl. _pedes_ (which see). Foot. (96.)

PES´SULUS, _n._ Cross-bone of the syrinx; bony bar across lower end of windpipe, at point of forking into the bronchi.

PETRO´SAL, _a._ (Used substantively.) Same as _petrous_.

PE´TROUS, _a._ Stony; hence, hard. The _petrous_ bone is an element of the temporal bone.

PHA´LANX, _n._; pl. _phalan´ges_. Commonly any bone of a finger or toe. Equivalent to internode or joint (not _articulation_). Properly in such application lacking the singular number, _phalanges_ being the row or series of the small digital bones, taken collectively. (120.)

PHARYNGE´AL, _a._ Pertaining to the pharynx.

PHAR´YNX, _n._ Back compartment of the mouth, leading directly into the œsophagus.

PHREN´IC, _n._ Pertaining to the diaphragm.

PHYS´ICAL, _a._ Bodily; material. Opposed to _mental_ or _psychical_.

PHYSIOG´NOMY, _n._ Countenance, in respect to temper of mind; general appearance, in respect to habits.

PHYSIOL´OGY, _n._ Science of animal or vegetable economy; science of bodily functions, processes, operations. It is less comprehensive than _biology_, or the science of life, as it takes account only of material or physical, not psychical, offices.

PI´A MA´TER, _n._ Soft vascular membrane immediately investing the brain.

PI´CINE, _a._ Woodpecker-like.

PICTU´RA, _n._ Pattern of coloring.

PIG´MENT, _n._ Coloring-matter.

PIL´EUS (also written _pileum_), _n._ The cap; top of head from base of bill to nape. (30.)

PIN´EAL BODY, _n._ A small organ associated with the brain.

PIN´ION, _n._ Part of the wing beyond the wrist exclusive of the feathers; usually the metacarpus and phalanges; the hand bone. Not technically used synonymously with _quill_ or _wing_.

PIN´NATED, _a._ Having little wing-like tufts of feathers on the neck.

PIN´NIFORM, _a._ An epithet of the penguin’s wing; fin-like.

PISCIV´OROUS, _a._ Fish-eating.

PITU´ITARY, _a._ That secretes mucus. _Pituitary membrane_, the mucous membrane of the nasal passages. _Pituitary gland_, a certain appendage of the brain.

PLA´GA, _n._ Stripe of color.

PLAN´TA, _a._ Back of tarsus, homologically the _sole_. (106.)

PLAN´TAR, _a._ Pertaining to the sole. A certain muscle is the _plantaris_.

PLAN´TIGRADE, _a._ Walking on the back of the tarsus as well as on the soles of the toes. Many pygopodous birds are plantigrade.

PLAS´MA, _n._ Colorless fluid of the blood.

PLAS´TIC, _a._ That may be moulded. Forming or serving to form; _histogenetic_. _Plastic force._ See NISUS FORMATIVUS.

PLEU´RA, _n._ Membrane lining the thorax and investing the lungs.

PLEURAPOPH´YSIS, _n._ Segment of the hæmal arch next to the centrum. The vertebral rib of a bird is a _pleurapophysis_.

PLEX´US, _n._ Union in network of nerves, vessels, or fibres. Said especially of the anastomosis of nerves.

PLI´CA ALA´RIS, or PLI´CA PREALA´RIS, _n._ The feathered fold of skin on the front border of the wing stretched by an elastic tendon from the shoulder to the wrist, rendering the smooth straight anterior border of the wing. (_Plica alaris_ is rarely used for the fold or bend of the wing.)

PLI´CA INTERDIGITA´LIS, _n._ Webbing between the toes. Same as _palama_.

PLI´CÆ PRIMITI´VÆ, _n. pl._ Primitive folds; certain parallel lines observed in the early embryonal trace.

PLU´MA, _n._ A feather in general. Compare PENNA and PLUMULA. (1.) A feather of which the two webs are equal and alike is called _isopogonous_: otherwise _anisopogonous_.

PLU´MAGE, _n._ The feathers, collectively; PTILOSIS (which see).

PLUM´BEOUS, _a._ Having the color of tarnished lead; dull bluish-gray.

PLUM´IPED, _a._ Having the feet feathered.

PLU´MOSE, PLU´MOUS, _a._ Feathery; in general, having feathers; feathered. Compare PENNACEOUS and PLUMULACEOUS.

PLU´MULA, _n._ A down feather, lacking certain qualities and parts of a _penna_.

PLUMULA´CEOUS, _n._ Downy. Compare PENNACEOUS.

PNEUMAT´IC, _a._ Relating to the respiratory system; permeated with air.

PNEUMOGAS´TRIC, _a._ Pertaining to lungs and belly; a name of the most extensive cranial nerve.

PODARTH´RUM, _n._ Foot-joint; the articulation of the toes collectively with the metatarsus. (100.)

PO´DIUM, _n._ Foot. (Same as _pes_.) Generally used, however, for the _toes_ collectively without the shank. (112.)

PODOTHE´CA, _n._ Whole envelope of tarsus and toes. (101.)

POGO´NIUM, _n._; pl. _pogonia_. Web or vanes of a feather. (147.) _Pogonium externum_, outer web (farthest from middle line of the body). _Pogonium internum_, inner web. See PLUMA.

POL´LEX, _n._ Thumb. The joint which bears the alula is so called, though it is homologous with the index or second finger. _Spina pollicaris_, or _Tuberculum pollicare_, the horny spur on the wing of some birds.

POLYG´AMOUS, _a._ Mating with more than one female, like the domestic cock.

POLYMOR´PHIC, _n._ Of many forms; consisting of, or containing, several different types of structure: as, a _polymorphic group_.

POLYMY´OID, _a._ Having numerous syringeal muscles; noting a group equivalent to _Oscines_.

POLYNO´MIAL, _n._ or _a._ Name of more than two words. Consisting of several words. The _polynomial_ nomenclature is obsolete.

POLYTO´KOUS, _a._ Multiparous; producing many young.

PONS, _n._ Bridge. Certain parts of the brain.

POPLITE´AL, _a._ Pertaining to the back of the knee.

POR´TAL CIRCULA´TION. Passage of blood from the capillaries of one organ to those of another, as is conspicuous in certain of the digestive viscera.

POSTAX´IAL, _a._ Situate on the external or posterior (ulnar or fibular) side of a limb.

POSTE´RIOR PORTION. (8.) See URÆUM.

POSTERIOR TOE. (125.) The hind-toe, or that one directed backward, is generally the hallux; often also the fourth or outer; rarely the second or inner. The hallux is generally meant by _posterior toe_.

POSTOR´BITAL, _a._ Situate behind the eye.

POW´DER-DOWN FEATH´ERS, _n. pl._ Peculiar imperfect feathers, in a matted patch, which grow continually, and as constantly break down, with a scurfy exfoliation, and pervaded with a greasy substance; they are especially conspicuous in the heron tribe, but are also found elsewhere.

PRÆAX´IAL, _a._ Situate on the internal or anterior (radial or tibial) side of a limb.

PRÆCO´CES, _n. pl._ An obsolete group of birds, able to run about and feed themselves at birth.

PRÆCO´CIAL, _n._ Belonging to the _Præcoces_; having the nature of _Præcoces_.

PRÆPEC´TUS, _n._ Fore-breast; region of the craw. Not well distinguished from _jugulum_.

PREMAX´ILLARY (_bone_), _a._ The foremost and principal bone of the upper jaw. _Intermaxillary_ is synonymous.

PREP´UCE, _n._ Foreskin. The homologous structure occurs in some birds. _Preputial_, pertaining to the foreskin.

PRESSIROS´TRAL, _a._ Having a bill like that of a plover. (Obsolete.)

PRESTER´NUM, _n._ Anterior segment of the breast-bone.

PRI´MARY, _n._; pl. _primaries_. Any one of the (usually ten, often nine, rarely eleven) large stiff quills growing upon the pinion or hand-bone, as distinguished from the secondaries which grow upon the forearm. They form the tip of the wing, and much of its surface.

PRI´MARY WING-COVERTS, _n. pl._ Those overlying the bases of the primaries.

PROCE´RES or PRO´CERI, _n. pl._ Same as RATITÆ (which see).

PROLIG´EROUS, _a._ See YOLK.

PRONA´TION, _n._ A particular movement of the radius upon the ulna, by which the hand turns over,—in birds it is very slight, if it occur at all. The reverse movement is termed _supination_. The muscles effecting it are _pronators_ and _supinators_.

PROÖT´IC, _a._ for _n._ An element of the auditory capsule.

PROSENCEPH´ALON, _n._ A certain tract of the brain, the third from behind.

PRO´TOPLASM, _n._ Primitive common embryonic tissue, out of which different organs and parts are formed.

PROTOVER´TEBRÆ, _n. pl._ First trace of the backbones.

PROTRAC´TILE, PROTRU´SILE, _a._ Susceptible of being thrust forward or out, as the tongue of most woodpeckers.

PROVENTRIC´ULUS, _n._ Part of gullet, usually enlarged, next to gizzard, having solvent glands for digestion. It is the true _stomach_ of a bird, as distinguished from the gizzard or grinding stomach.

PROX´IMAL, _a._ Proximate; nearest or next to any centre or axis. Opposed to _distal_ or _terminal_.

PSILOPÆ´DES, _n. pl._ A group of psilopædic birds, further distinguished by being born weak and helpless, fed and reared in the nest. The term _gymnopædes_ is synonymous.

PSILOPÆ´DIC, _a._ Having down growing only from the future pterylæ, as the precursor of the future plumage, to which it is subsequently affixed for a while and then falls off.

PSO´AS, _n._ Name of certain pelvic muscles.

PTERAPOPH´YSIS, _n._ Certain process of cranial bones.

PTER´NA, _n._ Heel-pad. (115.)

PTERO´MATA, _n. pl._ (This word is of uncertain meaning.) (89 ?)

PTER´YGOID (_bone_), _n._ A slender bone connecting the quadrate with the palatine.

PTER´YLA, _n._; pl. _pterylæ_. Area or _tract_ on the skin where feathers grow.

PTERYLOG´RAPHY, _n._ A description of the plumage, especially with reference to the distribution of the feathers on the skin.

PTERYLO´SIS, _n._ Plumage, considered with reference to its distribution on the skin.

PTI´LA, _n._ (This word is of uncertain meaning.) (86 ?)

PTILOPÆ´DES, _n. pl._ Ptilopædic birds. Such are generally able to run about at birth, or at least to feed themselves. _Dasypædes_ is synonymous.

PTILOPÆ´DIC, _a._ Clothed at birth with floccus, which sprouts not only from the future pterylæ, but also from apteria.

PTILO´SIS, _n._ Plumage. (3.)

PU´BIC, _a._ Pertaining to the pubis.

PU´BIS, _n._ The most anterior bone of the pelvis. In birds the _ossa pubis_ or _pubes_ are separate, there being no pubic symphysis, and directed more or less backward.

PUL´LUS, _n._ A chick; young bird, before its first complete plumage.

PUL´MONARY, _a._ Pertaining to the lungs; relating to respiration.

PUL´SUS, PULSE, _n._ Beating of the arteries.

PUNC´TATE, _a._ Dotted; pitted; studded with points.

PUNC´TUM SA´LIENS, _n._ First trace of the embryonic heart.

PUPIL´LA, _n._ Central black disc circumscribed by the iris; the pupil (a _hole_, not a substance).

PUPIL´LARY, _a._ Pertaining to the pupil.

PYGOP´ODES, _n. pl._ A group of birds distinguished by the far backward position, and deep burial, in common integument, of the legs.

PYGOP´ODOUS, _a._ Belonging to _Pygopodes_, or having the character of that group.

PY´GOSTYLE, _n._ Last coccygeal vertebra, of peculiar size and shape in recent birds; also called the _vomer_.

PYLOR´IC, _a._ Pertaining to the pylorus.

PYLO´RUS, _n._ Opening from gizzard into duodenum; _especially_, valve guarding this orifice.

PYR´IFORM, _a._ Pear-shaped.

Q.

QUADRAN´GULAR, _a._ Four-edged or four-angled.

QUAD´RATE, _a._ Squared.

QUAD´RATE BONE, _n._ See OS QUADRATUM. A peculiarly shaped bone interposed between the lower jaw and the rest of the skull.

QUADRILAT´ERAL, _a._ Four-sided.

QUADRILOC´ULAR, _a._ Four-chambered, as the heart of higher vertebrates is.

QUAR´RY, _n._ Prey of raptorial birds.

QUILL, _n._ See PENNA. (2, 75, 76, 145.)

QUI´NARY, _a._ Noting a certain absurd system of classification which presumes that there are _five_ types, or sets of objects, in every natural group.

QUIN´CUNX, _n._ Set of five, arranged thus, ⁙

R.

RA´DIAL, _a._ Pertaining to the radius.

RA´DII, _n. pl._ Barbs of a main feather.

RA´DII ACCESSO´RII, _n. pl._ Barbs of the supplementary feather.

RADIO´LI, _n. pl._ BARBULES (which see).

RADIO´LI ACCESSO´RII, _n. pl._ Barbules of the supplementary feather, aftershaft or hypoptilum.

RA´DIUS, _n._ Outer bone of forearm.

RA´MUS, _n._; pl. _rami_. Branch or fork. Gnathidea.

RAPH´E, _n._ Line of separation of two parts of an organ when prominent or otherwise distinguished.

RAPTO´RIAL, _a._ Pertaining to birds of prey.

RATI´TÆ, _n. pl._ Birds with flat sternum, as ostriches, emus or cassowaries, and the apteryx.

RAU´COUS, _a._ Hoarse-voiced.

REC´TRIX, _n._; pl. _rectrices_. Quills of the tail. (70.) (The singular is little used.)

REC´TUM, _n._ Lower straight gut.

REC´TUS, _a._ Name of certain muscles.

RECURVED´, _a._ Bent regularly and gradually upward.

REFLECT´ED, _a._ Turned backward.

REFLEC´TION, _n._ Play of color changing in different lights.

REG´IMEN, _n._ Diet.

RE´GIO, RE´GION, _n._ Portion of the body in any way distinguished; dorsal _region_; cervical _region_.

RE´MEX, _n._; pl. _remiges_. Quill of the wing. (75, 76.) (Little used in the singular.)

RE´NAL, _a._ Pertaining to the kidneys.

RE´TE, _n._ Same as _plexus_.

RETIC´ULATE, _a._ Marked with network of lines.

RETICULA´TION, _n._ Network; mosaic.

RET´INA, _n._ Expansion of the optic nerve within the eye, upon which images of objects are impressed.

RETRAC´TILE, _a._ Susceptible of being drawn back and driven forward as a hawk’s claw.

RETRORSE´, _a._ Directed backward.

RHACH´IS, _n._; pl. _rhachides_. Scapus exclusive of calamus; shaft of a feather, bearing the webs, without the hollow horny barrel. (146.) Also, the spinal column.

RHAMPHOTHE´CA, _n._ Covering of the whole bill. (12.)

RHI´NAL, _a._ Pertaining to the nose.

RHINENCEPH´ALON, _n._ Foremost tract of the brain, the fourth from behind.

RHINOTHE´CA, _n._ Covering of the upper mandible. (13.)

RHIZONYCH´IUM, _n._ Terminal bone of a toe bearing a claw. (122.) (Little used.)

RHOM´BOID, _a._ Lozenge-shaped. Name of a muscle of the shoulder-blade.

RIC´TUS, _n._ Gape of the mouth.

RIDGE, _n._ CULMEN (which see). (20.)

RI´MA, _n._ Outline of a slit-like opening.

RI´MA GLOT´TIDIS, _n._ Opening of the glottis.

RI´MA ORIS, n. Equivalent to COMMISSURE (which see).

ROS´TRUM, _n._ Bill; beak; projecting forepart of head of birds; of two jaws, upper and lower, consisting of a frame of certain bones over which is stretched unfeathered skinny or horny membrane, the rhamphotheca. (9.)

ROUND´ED (_tail_), _a._ Having the central feathers longest, the rest successively gradually and slightly shorter. A tail is _double-rounded_ when, with central feathers shorter than the next, the rest are graduated as before.

RU´DIMENT, _n._ A beginning.

RUDIMEN´TARY, _a._ Undeveloped; imperfectly elaborated; existing only in its beginnings.