Araceae 
the calla, Rifti, i ':>>', J-:tlii"/i''t, in a very common house- 
plant. Also called Aroi'li'n'. 
araceous (a-ra'shius), a. [< NL. araceus: see 
Araci-n:] Pertaining to tlic natural order of 
plants .Iriirin: 
arachidic (ar-a-kid'ik), a. [< ArarJiin(Arin-liiii-) 
+ -it-.] Pertaining to or derived rrm theearth- 
nnt, Anifhix hy/xHjwti : an,<inic/iiiiii' acid. 
Arachis (ar'a-kw), . [NL., < ( !r. />",t"f. npanos, 
apiiKir, sonic leguminous plant.] A small genus 
of leguminous plants, unlives of Bra7.il. The 
genus is mnarkalilu in the order im- it.- cl.m^it' d pedi- 
eel-like calyx-tiil.e, anil for the manner in whieli the 
growing stipe of the ovary bends downward ami, attain- 
iiiK a length of '2 or 3 inehes, pushes the ovary into the 
KTulinil, where it liejjins to enlarge anil ripen. Tin- !>(- 
known species is A. kjfpogtm. the eomiii"li peanut or 
groundnut, whieh is now enltivuteil in must uaiin cli- 
mate.-. ;ind is esteemed a valuable artiele of f 1. lt.-pnd 
when mature is oMomr, often contracted in the middle, 
wrinkled, of ft pale-yellow eolor, and oontaini t\vn .-ccds..i 
thr si/e of a ha/,ei nut, sweet in lla\<>r, e-]n cially when 
- 
.V/,1- 
287 
Their (the glands'] ducts ultimately enter the six promi- 
nent ani:'l'ni''li"/ iiiiiiinitillte. 
lltifli'H. Uiat. Invert., p. :ai. 
Arachnidial papilla, a minute ori- 
tiee through \vhieh the secretion of 
:ili ;il :n ImMillMi is potireil nut. 
arachnidium (ar-ak-nid'i- 
uni). n. ; pi. Ki-tirlniiditi (-a). 
[NL., < (!r. iipaxvifiutv, a cob- 
web, < a/mxvq, a spider, + dim. 
-/rW'.] The characteristic or- 
gan of tin' .li-iniriilii, or true 
spiders; flip glandular ap- 
paratus by wliieh the silky . 
threads forming cobweb are (i>i,.v)otaSpi- 
secreted and spun out. xnm- ',;;,.,"' 
berless minute glands, provided with 
-i ],;I!:LN t iu, i .. , nvtc the viscid material which hardens 
into silk when i Api'sed to the air. The glands have been 
divided into live kind- : aeiniform, ampnllate, .-e.4i.Ti ^:it-. 
tnlniliform. anil tulicnius. Their ilnets enter the arach- 
niilial manimillie, ami discharge through oriliers in the 
araehiiidial papilla-. 
arachnitis (ar-ak-ni'tis), w. A shortened form 
Common Peanut (Arachis hyfogira'}. 
a, a, flowers ; b, 6, ovaries oa lengthened stipes ; < , < , forming fruit ; 
ft, ripe pod ; e, pod opened, showing seeds. 
roasted, and yielding when pressed an oil not inferior to 
that of olives. The plant grows to the height of 1 or 2 feet. 
Arachla-oil, the oil expressed from the seeds of Arachi 
hypo'j&a, the fine limpid nut-oil of eoumierce, used as a 
substitute for olive-oil, and largely in soap-making. 
arachnactis (ar-ak-nak'tis), 11. [NL., < Gr. 
ap&xyri, a spider, + auric, a ray.] A name given 
to the free-swimming young of the genus Ed- 
wardsia (which see). The term was used as a genus 
name before the nature of these organisms was deter- 
mined. 
arachnid (a-rak'nid), w. One of the Aruchnida ; 
au arachuidan. 
Arachnida (a-rak'ni-da), n. pi. [NL., < Gr. 
apaxvt), a spider (see Aranea), + -irfa.] lu zool., 
a class name used with varying signification, 
(a) In Lamarek's and Latreille's systems of classification, 
one of three classes into which the Linnean Intsecta were 
divided, the other two being Cntstacea and Imecta ; pri- 
marily divided into Pulmonaria and Trachearia. (6) In 
Latreille's system, the second class of articulated animals 
with articulated legs, apterous and ametaholous. It was 
divided into two orders, Puhtwnaria and Trackearia, the 
former containing the spiders and scorpions, the latter the 
false scorpions, harvestmen, and mites, (r) A class of the 
phylum Arthroftftda, including the spiders, scorpions, false 
scorpions, harvestmen, and mites, with or without the 
bear-animalcules and the Pycnogonida and Pentantomida. 
They are apterous, ametabolous, articulate animals, with 
articulated legs. They are decephalized by the blending 
of the head with the thorax as a cephalothorax, normally 
hearing 8 legs, and never more ; the antenme are trans- 
formed into cheltc when present ; the abdomen is usually 
distinct but not segmented, or if segmented is not dis- 
tinctly separated from the cephalothorax, and does not 
l>ear limbs, the appendages being in the higher forms 
transformed into spinnerets ; the eyes are simple and gen- 
erally more than two in number ; the respiratory appara- 
tus is pulmonary or tracheal, or compounded of these two 
forms ; and their mode of progression is digitigrade. There 
are about 4,500 species, some of which are fossils occurring 
in the Silurian and Carboniferous. They are now divided 
arachnoid (a-rak'noid), a. and . [< Gr. 
foe5i7f, like a cobweb, < andxvi/, a spider's web, 
a spider, + <!w;, form.] I. a. 1. Of or pertain- 
ing to the Arachnida; arachnidan. 2. Like 
or likened to a cobweb: applied, in aiiat. (o) 
to the arachnoid of the brain (see II.); (6) to 
the hyaloid membrane or arachnoid of the eye 
(see II.). Arachnoid canal, cavity, etc. see the 
nouns.- Arachnoid membrane. Same as II., 2. 
Arachnoid tunic. Same as II., 8. 
II. H. 1. A kind of fossil madrepore. 2. In 
anat., the serous membrane enveloping the 
brain and spinal cord; the middle one of the 
three cerebrospinal meninges, between the 
dura mater and the pia mater. It was formerly re- 
garded as consisting of two layers, a visceral layer invest- 
ing the pia mater and a reflected parietal layer lining the 
dura mater, the two constituting a shut sac, like other 
serous membranes, inclosing a cavity called the arachnoid 
cavity, containing a serous fluid, the arachnoid fluid ; but 
the more modern view regards the arachnoid membrane 
as a single sheet external to the pia mater and attached to 
it, hut not following it into the sulci and other depres- 
sions of the brain. What was formerly called the cavity 
of the arachnoid is now termed the subdural space. The 
arachnoid is by some regarded as simply the outermost 
layer of the pia mater. Also called arachnoid rnembratu 1 , 
arachnoidea, aracftitoidett, and araneowt membrane. 
3. An old and disused name of the hyaline or 
hyaloid membrane within theeyeball, especially 
of that portion of it which contributes to form 
the capsule of the crystalline lens. 
arachnoidal (ar-ak-noi'dal), a. Pertaining to 
or of the nature of the arachnoid, in any sense 
of the word; arachnoid. 
arachnoidea, arachnoides (ar-ak-noi'de-a, 
-de?.), n. [NL.] Same as arachnoid, n., 2. 
arachnoiditis (a-rak-noi-di'tis), w. [NL., < 
arachnoidea + -itis.~\ Inflammation of the arach- 
noid membrane. 
arachnological (a-rak-no-loj'i-kal), a. Of or 
pertaining to arachnology. 
arachnologist (ar-ak-nol'o-jist), n. [< arach- 
nology + -ist."] One versed in arachnology. 
arachnology (ar-ak-nol'o-ji), . [< Gr. apdxvti, 
' 
tinea, Pentaslomidea (without Pycnagunitla). Synonymous 
with Acephala, 3, and Aura, 2. 
arachnidan (a-rak'ni-dan), a. and n. [< Ararh- 
n nl, i + -an.] I. a . Pertaining to the Arachnida. 
II. ii. One of the Araehnidn. 
arachnidia, . Plural of arachnidium. 
arachnidial (ar-ak-nid'i-al), a. [< ararltitidiniii 
+ -al.~\ Of or pertaining to an arachnidium. 
Arachnidial mammilla, one of the processes inU> 
which the ducts of the arachnidiilm enter; a spinneret. 
, 
a spider, + -'/.oyia, < /.ejeix, speak : see -ology.] 
The study of the Arachnida. 
Arachnopoda (ar-ak-nop'o-dii), n. pi. [NL., < 
Gr. apaxyr;, a spider, + novc (TOI!-) = E./oof.] In 
Dana's system of classification, a division of his 
suborder Cormostomata of Entomostraca. The 
term corresponds with Aranciformia or Pycno- 
qonida (which see). 
Arachnothera (a-rak-no-the'rii), w. [NL.,< Gr. 
apaxvri, a spider, + Oijpav, hunt, j The typical ge- 
nus of birds of the subfamily Arachnotherina;. 
There are numerous species, inhabiting the Indo-Malayan 
region, such as A. Umgirostris. Also Arachnothere*. 
Arachnotherinse (a-rak'no-the-ri'ne), w. j>l. 
[NL., < Araclinothera + -inn?.] A subfamily of 
Xectariniida; containing numerous species, 
chiefly East Indian and Oceanic, sometimes 
called spider-catchers, having long slender 
curved beaks like the sun-birds of the genera 
Drepanix, Cinnyris, etc. 
arack, . See arrack. 
aracouchini-resin (ar'a-ko-she'ui-rez'in), w. 
Same as acouchi-resin. 
aracuan (ar-a-kwau'), . [Of S. Amer. origin.] 
A name of one of the guans, Orttili.* iinieuan. 
Also written araucuan. 
arad (ar'ad), H. [< Arum + -arfl.] A plant of 
the natural order Aracea;. Lindley. 
Aradidae (a-rad'i-de), . pi. [NL., < Aradus 
+ -ida>.~] A family of heteropterous insects, 
characterized by their extremely depressed 
form and brown or fuscous coloration, and di- 
vided into Aradinm and Brachyrhynchiiue, 
Araliacese 
The family .-trur/ /</.*. wliieh contains the niost depressed 
Heteroptan in ndattee*. Stand Hat. //;./., ii. 283. 
Aradinae (ar-a-di'ne), H. i>l. [NL., < Aradus + 
-I/KI.] A subfamily of Arndida 1 , having a com- 
paratively long rostrum, tlic stenium grooved, 
tlic end ul the abdomen with a thin cleft and 
margin, and the head with an angular 
exterior to the .uitennai. It Is a large 
uronp, ^eni-rally distriiinted in America from the arctic 
regions to the tro]jics. 
Aradus (ar'a-dus), n. [XL., appar. < Or. apaAoc, 
a rumbling (rattling), var. of apafiof, a gnash- 
ing, chattering (rattling); cf. ufiuieiv, rattle, 
ring, as armor: in allusion to the loosc-ai mnreii 
appearance of tlic insects of this genus.] A 
genus of heteropterous inseets, typical of the 
subfamily Artnlititr. .1. rrrimtiix is a large spe- 
cies of the United States, half an inch long. 
araeometer, etc. See areometer, etc. 
araeostyle, . See irw//iV. 
araeosystyle, . See areosystylc. 
araeotlCt, . ami . See (in-nl/i: 
Aragonese (ar"a-go-nes' or -nez'), a. and n. 
[< sp. Arugimex, < Aragon.~\ I. a. Pertaining 
to Aragon or to its inhabitants. 
II. . ning. or pi. An inhabitant or the in- 
habitants of Aragon, one of the great divisions 
(formerly a kingdom) of Spain, in the north- 
eastern part. 
Sometimes spelled Arragonese. 
aragonite (ar'a-go-nit), . [< Aragon, a divi- 
sion of Spain. -1- -life 2 .] Calcium carbonate crys- 
tallizing in the orthorhombic system. It Is iden- 
tical with calcite in chemical composition, but differs from 
it in crystalline form and in some of its physical proper- 
ties; for example, its specific gravity is 2.9, while that of 
calcite is 2.7. It occurs often in transparent acicular crys- 
tals, and also as a deposit from waters carrying lime. A 
white variety, having a delicate coralloid form, Is called 
Jloiferri (flower of iron), from the fact of its occurrence 
with iron ores. 
aragu (ar'a-g8), n. [Canarese aragu, Telugu 
arakku, ult. < Skt. lakuhd, lac: see toe 1 .] Crude 
sticklac. See sticklac. 
araguato (ar-a-gwii'to), n. [S. Amer. ; cf. ara- 
62.] A kind of howling monkey of South 
America, of the genus Mycetes, M. ursinus, or 
the ursine howler. It is the largest of the new-world 
monkeys hitherto noticed, Its length being nearly 3 feet, 
while the tail reaches to even a greater length. Like 
all other members of the family, it is characterized by 
its discordant and dismal yells, which can be heard at the 
distance of a mile. See cut under hoicler. Also called 
guareba, guariba. 
araignee (a-ra-nya'), " [F. araignte, a spider, 
formerly also a spider's web, < LL. 'araneata. 
a spiders web, (. L. aranea, spider: see Aranea.] 
In fort., a kind of underground work consisting 
of several branches or galleries starting from 
one point, like a spider's web. 
araint, [Mod. only dial., also arrow, arrand, 
< ME. arain, arein, arayne, etc., train, erayne, 
etc., < OF. araigne, aragne, iraigne, iragne = 
Pr. aranha, eranha = Sp. arafia = Pg. aranAa = 
It. aragna, a spider, < L. aranea, a spider, a 
spider's web: see^ranea.] A spider. 
Arainae (ar-a-i'ne), 11. pi. [NL., < Ara 2 + -ii<e.] 
Same as Arina: 
araiset (a-raz'), r. t. [< ME. araisen, areisen, 
raise up, < n- (< AS. a-) + raisen, reisen, raise: 
see a- 1 and raise.] Same as raise. 
[A medicine] whose simple touch 
Is powerful to arait<c King Pepin. 
Shak., All's Well, it 1. 
arak, . See arrack. 
Arakanese, a. and n. See Aracanese. 
arake (a-rak'),j/rej>. phr. as adv. or a. [< a 3 + 
rate.] Naut., on the rake ; inclined from the 
perpendicular. 
araki (ar'a-ki), H. [Cf. arki; see arraek.'J An 
Egyptian intoxicating drink prepared from the 
dibs or honey of dates ; a kind of arrack. 
My guardians and attendants . . . used to fetch arajci 
in a clear glass bottle, without even the decency of a cloth, 
and the messenger twice returned from these errands de- 
cidedly drunk. R. F. Burton, El-Medinah, p. 487. 
Aralia (a-ra'li-a), w. [NL.: origin unknown.] 
A genus of plants with small flowers arranged 
in umbels, and succulent berries, the type of the 
natural order Araliacete. 
Araliaceae (a-ra-li-a'se-e), n. pi. [NL., < Ara- 
Un + -acca:.~\ A natural order of plants nearly 
related to the Umbclliferte, from which they are 
distinguished chiefly by their three- or more 
celled fruit, simple epigynous disk, usually 
valvate corolla, and more shrubby habit. The 
order is most largely represented in warm and tropical 
countries, and to it belongs the ivy, Hedrra Helix. <>in- 
seng, which is highly esteemed by the Chinese as a stimu- 
lant, is produced by Panax Schinneng, a plant found in 
northern Asia. The ginseng of North America, Aralia 
quiiwnefolia, is less valued. A species of Aralia, A. nudi- 
faulis, is used in North America as a substitute for sarsa- 
