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.