Retifera 
Retifera (i-e-tif'e-ra), w. pi. [XL., neut. pi. of 
rctifcrits: see reitferous.] A family of DeBlain- 
ville's cervicobranchiate Paracephalopltora her- 
miiiiliriKlilii, based on the genus Patella; the true 
limpets. See PaMlitlie. 
retiferous (re-tif'e-rus), a. [< NL. retiferus, < 
L. rete, a net, + mm = E. bear 1 .] Having a 
rete or retia; reticulate. 
retiform (re'ti-form), a. [< OF. retiforme, F. 
retiforme = Pg. It. retiforme, < NL. retiformis, < 
L. rete, a net, + forma, shape.] 1. In anat. and 
zool., retial; like a network or rete in form or 
appearance; reticular: as, the retiform coat of 
the eyeball. 2. In hot., net-like; reticulate. 
Retiform connective tissue. See adenoid tissue, under 
adenoid. 
retina (ret'i-ua), n. [= OF. refine, rectine, F. 
refine = Sp. Pg. It. retina, < NL. retina, retina: 
so called because resembling 
fine network, < L. rete, a net: 
see rete.] The innermost and 
chiefly nervous coat of the pos- 
terior part of the eyeball, be- 
tween the choroid coat and 
the vitreous humor. It extends 
from the entrance into the eyeball of 
the optic nerve toward the crystalline 
lens, terminating in the ora serrata. 
A modified division of the retinal 
structure is, however, continued for- 
ward as the pars ciliaris retinee. The 
retina consists of a delicate and com- 
plex expansion and modification of 
the optic nerve, supported by a net- 
work of connective tissue. It may be 
divided into ten layers: (1) internally, 
next the hyaloid membrane of the 
vitreous humor, the internal limiting 
membrane, formed of the expanded 
bases of the fibers of Miiller ; (2) the 
fibers of the optic nerve ; (3) layer of 
ganglion-cells ; (4) internal molecular 
or granular layer; (5) inner nuclear ofaSectionoftheNer 
layer ; (6) external molecular or gran- vous Elements of the 
ular layer; (7) external nuclear lay- 
er; (8) external limiting membrane, 
which is connected with the ends of 
Miiller's fibers; (9) layer of rods and 
cones, or bacillary layer; (10) pigmen- 
tary layer. In the center of the back 
part of the retina, near the line of 
the optic axis, is the macula lutea, the 
most sensitive part of the retina ; and 
in the center of the macula is a de- 
pression, the fovea centralis, in which 
the rods are absent. The color of the 
macula is due to a yellow pigment. 
About one tenth of an inch internally 
to the fovea is the point of entrance 
of the optic nerve with its central ar- 
tery; the retina is incomplete at this 
point, and constitutes the "blind 
spot." The nerve-fibers have been 
estimated to number 400,000 broad 
and as many narrow fibers, and for 
each fiber there are 7 cones, 100 
rods, and 7 pigment-cells. The retina 
serves the purpose of vision in being the organ through 
or by means of which vibrations of luminiferous ether ex- 
cite the optic nerve to its appropriate activity. See eyei. 
Central artery and vein of retina. See central. 
Coarctate retina, a funnel-shaped condition of the reti- 
na, due to the accumulation of fluid between the retina 
and the choroid. Epilepsy Of the retina. See epilepsy. 
Pigmentary layer of the retina. See pigmentary. 
Rod-and-cone layer of the retina, a layer composed of 
minute elongated cylindrical and flask-shaped elements 
arranged vertically to the pigmentary layer of the retina, 
and parallel to one another. Also called columnar layer, 
bacUlar layer, bacillary layer, stratum baciUosum, stratum 
cylindrorum, Jacob's membrane, Jacobian membrane. 
retinaculum (ret-i-nak'u-lum), n.; pi. retinacula 
(-la). [= F. retinacle, < L. retinaculum, a band, 
tether, halter, tie, < retinere, hold back: see re- 
tain.] 1. Inbot.: (a) A viscid gland belonging to 
the stigma of orchids and asclepiads, and hold- 
ing the pollen-masses fast. (6) The persistent 
and indurated hook-like funiculus of the seeds 
in most Acanthacese. A. Gray. 2. In anat., a 
restraining band; a bridle or frenum: applied 
to such fibrous structures as those which bind 
down the tendons of muscles; also to the bridle 
of the ileocsecal valve. 3. In entom., specifi- 
cally, a small scale or plate which in some in- 
sects checks undue protrusion of the sting. 
4. In surg., an instrument formerly used in 
operations for hernia, etc Retinacula of Mor- 
gagnl, or retinacula of the Ileocsecal valve, the mem- 
branous ridge formed by the coalescence of the valvular 
segments at each end of the opening between the ileum 
and the colon. Also cal led frena. Retinaculum pero- 
neorum, a fibrous band which holds in place the tendons 
of the peroneal muscles as they pass through the grooves 
on the outer side of the calcaneum. Retinaculum ten- 
dineum, a transverse band of fibrous tissue which in the 
region of joints passes over the tendons, and serves to 
hold them close to the bone, as the annular ligament* of 
the wrist and the ankle. 
retinal (ret'i-nal), a. [< retina + -al.] Of or 
pertaining to tne retina: as, retinal structure; 
retinal expansion; retinal images. 
Diagrammatic View 
Retina, the merely 
connective elements 
being not represented: 
magnified about 150 
diameters: *,therods; 
f, the cones; *', c'. 
granules of the outer 
nuclear layer, with 
which these are con- 
nected ; d, d', inter- 
woven very delicate 
nervous fibers of the 
outer molecular layer, 
from which fine ner- 
vous filaments bearing 
granules of the inner 
nuclear layer ^/"pro- 
ceed toward the front 
surface; ^.^.continua- 
tionof thesefine nerves 
in the inner molecular 
layer, which become 
convoluted and inter- 
woven with the pro- 
cesses of the ganglion- 
of the optic nerve. 
5123 
Surely if form and length were originally retinal sensa- 
tions, retinal rectangles ought not to become acute or ob- 
tuse, and lines ought not to alter their relative lengths as 
they do. W. James, Mind, XII. 627. 
Retinal apoplexy, hemorrhage into the tissues of the 
retina. Retinal horizon, Hulmholtz's term for the 
horizontal plane which passes through the transverse 
axis of the eyeball. Retinal image, the image of ex- 
ternal objects formed on the retina. Retinal ischemia, 
partial or complete anemia of the retina, caused by con- 
traction of one or more branches of the arteria centralis 
retinEe. Retinal purple. Same as rhodopsin. 
retinalite (re-tin'a-lit), H. [Prop. *rhetinolitc, 
< Gr. fnrrivr/, resin (see resin), + /.itiof, stone.] A 
green translucent variety of serpentine, from 
Canada, having a resinous aspect. 
retinerved (re'ti-nervd), a. [< L. rete, net, + 
nernts, nerve, + -frf 2 .] In hot., netted-veined ; 
reticulate. 
retinite (ret'i-ult), . [= F. retinite, < Gr. />//"'- 
vi], resin (see resin), + -!te 2 .] 1. Highgate 
resin. 2. One of the French names for pitch- 
stone or obsidian, occasionally used in this 
sense by writers in English, especially in trans- 
lating from the French. See cut under ftuidtil . 
retinitis (ret-i-ni'tis), n. [NL., < retina + -iff*.] 
Inflammation of the retina Albumlnurtc reti- 
nitis, retinitis caused by Bright's disease. Diabetic 
retinitis, retinitis occurring in diabetes. Nephritic 
retinitis. See nephritic. Retinitis plgmentosa, a 
chronic interstitial connective-tissue proliferation of all 
the layers of the eye, with development of pigment due to 
a proliferation of the pigment-layer, and with final atro- 
phy of the optic nerve. 
retinochoroiditis (ret"i-no-k6-roi-di'tis), H. 
[NL., < retina + clioroid + -itis.] In patliol., 
same as cliorioretinitis. 
retinogen (ret'i-no-jen), n. [< NL. retina, reti- 
na, + -gen, producing : see -gen.'] The outer one 
of two layers into which the ectoderm of the 
embryonic eye of an arthropod may be differ- 
entiated: distinguished from gangliogen. 
retinoid (ret'i-noid), a. [<C Gr. prjrivri, resin, + 
tHof, form.] Resin-like or resiniform ; resem- 
bling a resin. 
retinophora(ret-i-nof'o-ra), n, ; pi. retinopltorse 
(-re). [NL.,\ retina, retina, + Gr. -^opof, < Qepetv 
= E. bear*.] One of those cells of the embry- 
onic eye of arthropods which secrete the chiti- 
nous crystalline cone on that surface which is 
toward the axis of the ommatidium. Also called 
vitrella. 
retinoscopy (ret'i-no-skp-pi), . [< NL. retina 
+ Gr. moma, < mcoTreiv, view.] 1. Skiascopy. 
2. Examination of the retina with an ophthal- 
moscope. 
retinoskiascopy, n. Same as skiascopy. 
Retinospora (ret-i-nos'po-ra), . [NL. (Siebold 
and Zuccarini, 1842), < Gr. pririvit, resin, + ovopa, 
seed.] A former genus of coniferous trees, now 
united to Cltamsecyparis, from which it has been 
distinguished by the conspicuous resin-ducts in 
the seed-coat. Several species are often cultivated in 
America under the name retinospora. They are also 
known as Japanese cypress C. (R.) obtitsa as the Japanese 
tree-ofJhe-sun, C. (R.) pixifera, as sawara. They are in use 
for lawn-decoration, and for hedges, especially the golden 
retinospora, consisting of cultivated varieties (var. aurea) 
of both these species, with yellowish foliage. 
retinue (ret'i-nu, formerly re-tin'u), n. [< ME. 
retenue, < OF. retenue, a retinue, F. retenue, re- 
serve, modesty (= Pr. retenguda ; ML. reflex re- 
tenuta), fern, of retenu, pp. of retenir, < L. reti- 
nere, retain: see retain.] 1. A body of retainers; 
a suite, as of a prince or other great personage ; 
a train of persons; a cortege ; a procession. 
Not only, sir, this your all-licensed fool, 
But other of your insolent retinue 
Do hourly carp and quarrel. Shak., Lear, i. 4. 221. 
To horse we got, and so 
Went forth in long retinue following up 
The river as it narrow'd to the hills. 
Tennyson, Princess, iii. 
2. An accompaniment; a concomitant. [Rare.] 
The long retinue of a prosperous reign, 
A series of successful years. 
Dryden, Threnodia Augustalis, 1. 507. 
TO have at one's retlnuet, to have retained by one. 
He hadde eek wenches at his retenue. 
Chaucer, Friar's Tale, 1. 56. 
retinula (re-tin'u-la), n.; pi. retimdx (-le). 
[NL., dim. of retina, retina : see retina.] In en- 
tom., a group of combined retinal cells, bearing 
a rhabdom. Gcgenbaur, Comp. Anat. (trans.), 
p. 264. 
retinular (re-tin'u-lar),. [< retinula + -ai-3.] 
Of or pertaining to a retiuula. 
retiped (re'ti-ped), a. [< L. rete, a net, + pes 
(ped-) = E. foot.] Having reticulate tarsi, as 
a bird. 
retiracy (re-tir'a-si), . [Irreg. < retire + -acy, 
appar. after the analogy of privacy.] Retire- 
ment; seclusion. [Recent.] 
retire 
The two windows were draped with sheets, . . . the 
female mind cherishing a prejudice in favor of retiracy 
during the night-capped periods of existence. 
L. M. Alcott, Hospital Sketches, p. 61. 
He, ... in explanation of his motive for such remorse- 
less retiracy, says : "I am engaged in a business in which 
my standing would be seriously compromised if it were 
known I had written a novel. " 
The Critic, March 1, 1884, p. 97. 
retirade (ret-i-rad'), >i. [< F. retiratle (= Sp. 
Pg. (milit.) retirada = It. ritirata), < retirer, re- 
tire : see retire. Cf. tirade.] In fort., a kind of 
retrenchment in the body of a bastion or other 
work, to which a garrison may retreat to pro- 
long a defense . It usually consists of two faces, 
which make a reentering angle. 
retiral (re-tlr'al). H. [< retire + -al.] The act 
of retiring or withdrawing ; specifically, the act 
of taking up and paying a bill when due : as, 
the retiral of a bill. Cotgrave. (Imp. Diet.) 
retire (re-tir'), v. ; pret. and pp. retired, ppr. 
retiring. ' [< OF. retirer, F. retirer (= Pr. Sp. 
Pg. retirar = It. ritirare), retire, withdraw, < 
re-, back, + Wrcr.draw: see tire 2 , andcf. attire.] 
1. trans. 1. To draw back; take or lead back; 
cause to move backward or retreat. 
He, our hope, might have retired his power, 
And driven into despair an enemy's hope. 
Shak., Rich. II., ii. 2. 4t>. 
The locks between her chamber and his will, 
Each one, by him enforced, retires his ward. 
Shak., Lucrece, 1. 303. 
2f. To take away; withdraw; remove. 
Where the sun is present all the year, 
And never doth retire his golden ray. 
Sir J. Dacies, Immortal, of Soul, Ded. 
I will retire my favorable presence from them. 
Leightan,. Works (ed. Carter), p. 366. 
3t. To lead apart from others ; bring into re- 
tirement ; remove as from a company or a fre- 
quented place into seclusion : generally with a 
reflexive pronoun. 
Beseech you, give me leave to retire myself. 
Shak., Cor., i. 3. 30. 
Good Dioclesian, 
Weary of pomp and state, retires himself, 
With a small train, to a most private grange 
In Lombardy. 
Fletcher (and another '!), Prophetess, v. (cho.). 
4. To withdraw ; separate ; abstract. 
Let us suppose . . . the soul of Castor, while he is sleep- 
ing, retired from his body. 
Locke, Human Understanding, II. i. 12. 
So soon as you wake, retire your mind into pure silence 
from all thoughts and ideas of worldly things. 
Penn, Advice to Children, ii. 
5. Specifically, to remove from active service ; 
place on the retired list, as of the army or 
navy. 6. To recover; redeem; regain by the 
payment of a sum of money; hence, specifi- 
cally, to withdraw from circulation by taking 
up and paying: as, to retire the bonds of a 
railway company ; to retire a bill. 
If he be furnished with supplies for the retiring of his 
old wardrobe from pawn. 
B. Jonson, Cynthia's Revels, ii. 1. 
Many of these [State banks] were in being before the 
enactment of the national banking law, declined reorgani- 
zation under its terms, and were obliged to retire their 
circulation. Harper's Mag., LXXX. 459. 
II. intrans. 1. To draw back; go back; re- 
turn. 
He'll say in Troy, when he retires, 
The Grecian dames are sunburnt, and not worth 
The splinter of a lance. Shak., T. and C., i. 3. 281. 
At his command the uprooted hills retired 
Each to his place. Milton, P. L., vi. 781. 
2. To draw back; fall back; retreat, as from 
battle or danger. 
The winter coming on, and sickness growing 
Upon our soldiers, we will retire to Calais. 
Shak., Hen. V., iii. 3. 56. 
Here Nature first begins 
Her farthest verge, and Chaos to retire 
As from her utmost works, a broken foe. 
Milton, P. L., ii. 1038. 
At me you smiled, but nnbeguiled 
I saw the snare, and I retired. 
Tennyson, Lady Clara Vere de Vere. 
3. To withdraw; go away or apart; depart; 
especially, to betake one's self, as from a com- 
pany or a frequented place, into privacy ; go 
into retirement or seclusion ; in the army or 
navy, to go voluntarily on the retired list. 
If you be pleased, retire into my cell 
And there repose. Shak., Tempest, iv. 1. 161. 
The mind contracts herself, and shrinketh in, 
And to herself she gladly doth retire. 
Sir J. Dames, Immortal, of Soul, Int. 
Q. Mary dying a little after, and he [Philip] rrtirini/, 
there could be nothing done. IIouvll, Letters, I. vi. 3. 
Banish'd therefore by his kindred, he retires into Greece. 
Milton, Hist. Eng., i. 
