Acanthoph r actae 
Acanthophractae (a-kan-tho-frak'te), n. pi. 
[NL., <Gr. anavda, a thorn, + QpaKTof, included, 
verbal adj. of ejpdaaeiv, fence in, inclose.] A 
suborder of acantharian radiolarians, having a 
skeleton of 20 radial spicules regularly grouped 
according to J. Muller's law, and a fenestrated 
or solid shell around the central capsule formed 
by connected transverse processes. 
acanthopod (a-kan'thp-pod), a. and n. [< Acan- 
thoftpdaT] I. a. Having spiny feet. 
II. n. An animal with spiny feet ; one of the 
Acanthopoda. 
Acanthopoda (ak-an-thop'o-da), n.pl. [NL., 
<Gr. anavSa, a spine, + ireef (nod-) = E.foot] 
In Latreille's system of classification, a group 
of clavicorn beetles, the first tribe of the second 
section of Clavicorncs, with broad flattened feet 
beset outside with spines, short 4-jointed tarsi, 
depressed body, dilated prosternuin, and curved 
11-jointed antennae longer than the head. The 
group corresponds to the genus Heterocerwi of Bose. 
These insects burrow in the ground near water. 
acanthoptere (ak-an-thop'ter), n. [See Acan- 
thopteri] One of the Acanthopteri. 
Acanthopteri (ak-an-thop'te-ri), n.pl. [NL., 
pLolaeanthopteriui: see acanihopteroug.] 8ame 
as Acanthopterygii (b). 
acanthopterous (ak-an-thop'te-rus), a. [<NL. 
acanthoptems, < Gr. aitavOa, a spine, + irrep6v, a 
wing, = E. feather.] 1. Spiny-winged, as the 
cassowary. 2. Having spiny fins; of the nature 
of the Acanthopteri or Acanthopterygii ; acan- 
thopterygious. 3. Having spines : as, anacan- 
thopterous fin. 
acanthopterygian (a-kan*thop-te-rij'i-an), a. 
and n. I. a. Of or pertaining to the Acan- 
thopterygii; having the characters of the Acan- 
thopterygii. 
II. n. One of the Acanthopterygii ; a fish 
with spiny fins. 
Acanthopterygii (a-kan'thop-te-rij'i-i), n. pi. 
[NL., pi. of acanthopterygius : see acanthopte- 
rygious.] A large group of fishes to which vari- 
ous limits and values have been assigned. The 
name was introduced into systematic ichthyology by Wil- 
Inghby and Ray, adopted by Artedi, and largely used by 
subsequent naturalists, (a) In Cuvier's system of classifi- 
cation, the first order of fishes, characterized by hard spiny 
rays in the dorsal tins, as the common perch, bags, and 
mackerel ; the spiny-nnned fishes, (b) In Gunther's system 
of classification, an order of teleosts with part of the rays 
of the dorsal, anal, and ventral fins spiny, and the lower 
pharyngeals separate. The last character eliminates the 
labrids and several other families retained by Olivier, but 
by Giinther referred to a special order Pharyntjottnathi. 
(c) In Gill's system of classification, a suborder of Teleo- 
cephali with ventrals thoracic or jugular (sometimes sup- 
pressed), spines generally in the anterior portion of the 
dorsal and anal fins and to the outer edges of the ventrals, 
normal symmetrical head, and pharyngeal tones either 
separate or united. The pediculate, hemibranchiate, and 
opisthomotis fishes are excluded as different orders, and 
the Percesoces, Rherjno/iteri, Discocephali, Taeniosmni, and 
Xenopteryr/ii as special suborders. Even thus limited, it 
comprises more species than any other suborder or order 
of fishes. The perch, bass, porgy, mackerel, and swordfish 
are examples. 
acanthopterygious (a-kan^thop-te-rij'i-us), a. 
[< NL. acanilioptcryglus, < Gr. aaaviia, a thorn, a 
spine, + TTTtp'vytov, the fin of a fish, dim. of vrkpv^, 
a wing, a fin, < vrepAv, a wing, = E. feather,] 
Having the characters of the Acanthopterygii or 
spiny-finned fishes ; belonging to the Acantho- 
pterygii ; acanthopterygian. 
Acanthorhini (a-kan-tho-ri'nl), n. pi. [< Gr. 
anavOa, a spine, + pic, piv, nose.] An ordinal 
name suggested by Bonaparte, 1831, as a sub- 
stitute for Holocephala (which see). 
Acanthorhynchus (a-kan-tho-ring'kus), n. 
[NL.,<Gr. anavOa, a thorn, + p'vyxos, snout.] 1. 
A genus of Australian birds, of the family 
Meliphagidce and subfamily Myzomelinas: so 
called from their slender acute bill. The spe- 
cies are A. tenuirostrig and A. superciliosus. J. 
Gould, 1837. 2. A genus of helminths. Diesing, 
1850. 
acanthosis (ak-an-tho'sis), n. [NL., < Gr. O.KOV- 
t)a, spine, + -osis.] A name applied to any dis- 
ease affecting primarily the stratum spinosum 
(prickle-cells) of the epidermis. 
Acanthoteuthis (a-kan-tho-tu'this), n. [NL., 
< Gr. anav6a, a thorn, + revOic, a squid.] A genus 
of fossil cephalopoda, of the family Belemnitidee, 
characterized by the almost rudimentary con- 
dition of the rostrum and the large pen-like 
form of the proostracum. It occurs in the Triassic 
rocks, and is notable as the oldest known cephalopod of 
the dibranchiate or acetabuliferous order. 
Acanthotheca (a-kan-tho-the'ka), n.pl. [NL., 
< Gr. axavOa, a thorn, + Bqiai, a case.] Same as 
Pentastomidea. Also written Acanthotheci. 
acanthoUS (a-kan'thus), a. [<Gr. aitavBa, a 
spine : see acantha and -ous.] Spinous. 
Leaf of Acanthus 
spinosus. 
acanthurid (ak-an-thu'rid), M. A fish of the 
family Acanthurieke. 
Acanthuridae (ak-an-thu'ri-de), M. pi. [NL., 
< Acaitthiirus + -idw] A family of acantho- 
pterygian fishes typified by the 
genus Acanthurus, to which va- 
rious limits have been ascribed . 
See Ti-ulliididir. 
Acanthurus (ak-an-thu'rus), 
. r_NL., < Gr. iucavOa, spine, 
+ ovpa, tail.] 1. The repre- 
sentative genus of the fami- 
ly Acanthurid(E, characterized 
by spines on 
the sides 
of the tail, 
whence the 
name. The 
species are nu- 
merous in the 
tropical seas, 
and are popularly known as doc- 
tors, surgeons, surgeon-fishes, bar- 
ters, etc. Synonymous with Teu- 
this. 
2. A genus of reptiles. Dau- 
din. 3. A genus of coleop- 
terous insects. Kirby, 1827. 
Acanthus (a-kan'thus), n. 
[L. (> Sp. It. aeanto = Pg. 
acantho = F. acanthe), < Gr. 
anavOoc,, brankursine, also a 
thorny Egyptian tree, < d/cov- 
Oa, a thorn : see acantha.] 
1. In hot., a genus of tall 
herbaceous plants of south- 
ern Europe and Africa, nat- 
ural Order AcanthacecB. They Acanthus. Inflorescence, 
have large spinosely toothed leaves, 
and are sometimes cultivated for the sake of their beauti- 
ful foliage. 
2. [I. c.] The common name of plants of this 
genus. 3. In zool., a genus of crustaceans. 
4. [I.e.] Inarch., 
a characteristic 
ornament derived 
from or resem- 
bling the conven- 
tionalized foliage 
or leaves of the 
acanthus, used in 
capitals of the Corinthian and Composite or- 
ders, and in Roman, Byzantine, medieval, and 
Renaissance architecture generally, as upon 
friezes, cornices, modillions, etc. 
AcanthylllS (ak-an-thil'is), n. [< L. acanthijl- 
lis, < Gr. axavOv^Aif, the pendulous titmouse, 
dim. of amvOic,, the goldfinch or linnet, < anavda, 
a thorn: see acantha] A genus of American, 
Indian, and Australian birds of the swift family, 
Cypselidai; the spine-tailed swifts, now usually 
referred to the genus Chaitura. Usually written 
Acanthylis. Boie, 1826. 
acanticone, acanticon (a-kan'ti-kon, -kon), n. 
[< Gr. aur], a point, + avri, against, + niJvof, a 
cone.] A variety of epidote ; arendalite (which 
see). 
a cappella, alia cappella (a oral'la ka-pel'la). 
[It. : a (L. ad), to, according to ; alia (= a la), 
to the ; cappella, church, chapel, church musi- 
cians: see chapel] In the style of church or 
chapel music. Applied to compositions sung without 
instrumental accompaniment, or with an accompaniment 
in unison with the vocal part : as, a mass a cappeUa. 
acapsular (a-kap'su-lar), a. [< Gr. a- priv. + 
capsule.] Without a capsule. 
acardia (a-kar'di-a), . [NL.: see acardius.] 
In teratol., absence of a heart. 
acardiac (a-kar'di-ak). a. [< NL. acardiacus, 
adj.,< Gr. a- priv. + napoiaK6f,<. napdia, the heart: 
see a- 18 and cardiac] Without a heart. 
acardiacus (ak-ar-di'a-kus), .; pi. acardiaci 
(-si). [NL. : see acardiac.] In teratol., that 
parasitic part of a double monster in which the 
heart is absent or rudimentary. Acardiacus amar- 
phus is a shapeless mass covered with skin. Acardiacus 
aconnus has a head.lwhile the thorax and abdomen are ru- 
dimentary. In acardiacus acephalus the head is lacking, 
the thorax rudimentary, and the pelvis and posterior limbs 
well developed. Acardiacus ancfps has a well-developed 
trunk and rudimentary head, limbs, and heart. 
acardius (a-kar'di-us), n. ; pi. acardii (-i). 
[NL., < Gr. anapSiof, without a heart, < a- priv. 
+ Kap6ia="E. heart.] Same as acardiacus. 
acarian (a-ka'ri-an), a. [(.Acarus, q. v.] Of or 
pertaining to the order Acarida ; belonging to 
or resembling the genus Acarus. 
In some cases of acne, an acarian parasite, called by 
Owen theDemodex folliculorum, is present in the affected 
follicle. T. W. Richardson, Prevent. Sled., p. 261. 
Acanthus in Roman Architecture. 
acatalectic 
acariasis (ak-a-ri'a-sis), n. [NL., < Acarus + 
-iasis.] A skin-disease caused by an acarian 
parasite. 
acaricide (a-kiir'i-sid), w. [< Acarus + L. -ruin, 
a killer, < cwdere, kill. Cf . lioniiridr, parricide, 
matricide.] A substance that destroys mites. 
acarid (ak'a-rid), n. [< Acarida] One of the 
Aciirida; a mite. 
Acarida (a-kar'i-da), n. pi. [NL., < Acarus 
+ -ida.] An order of the class Arnrhnida, in- 
cluding those insects, as the mites, ticks, itch- 
insects, etc., which are without a definite line 
of demarkatiou between the unsegmented ab- 
domen and the cephalothorax, the head, thorax, 
and abdomen appearing united in one. They 
are with or without eyes ; the mouth is either suctorial or 
masticatory ; the respiration is eitheft trachea! or dermal ; 
and the legs are 8 in number in the adult and in the 
young, being in some cases terminated by suckers, in 
others by set. There are several families of Amriila. 
with numerous genera and species, mostly oviparous and 
generally parasitic, but many are found in excrementi- 
tious or decaying animal matter, or on plants, while some 
are marine and others live in fresh water. Those which 
live on plants are often very injurious to vegetation^ and 
frequently form a kind of gall, sometimes resembling a 
fungus or a bird's nest, as the "witch-knot" of the birch, 
caused by members of the genus Phytoptun. The garden- 
mites (TYewnWdidoO, including the harvest-tick (Leptvn 
autumnal^), the spider-mites (Gamwndon), and the wood- 
mites (Oribatidoe) live mostly upon vegetation. The true 
ticks (Ixodidce) attach themselves to the bodies of various 
animals ; the water-mites 
(Hydrarachtiida?) are, at o ^ 
least in part, parasitic up- 
on animals, such as aqua- 
tic insects, mollusks, and 
even mammals. The 
cheese-mite, Acarus do- 
mftticus, is typical of the 
family Acarida; and of the 
whole order. The mange- 
mite, Veitwdex follixulo- 
rHm, type of the family 
DemodicidtK, is found in 
the sebaceous follicles of 
man, as well as in the dog. 
The itch-mite, which bur- 
rows into the skin, is the 
Sarcopteg scabiei, type of 
the family Sarcoptida. 
The mites and ticks are 
also called collectively 
Acaridea, acaridans, 
Acarina, and Mmwtneru- 
ttoinata. See cuts under 
flour-mite, itch-mite, and 
narcert-oug. 
Acaridae (a-kar'i-de), . pi. [NL., < Acarus 
+ -i<la>.] A family of the order Acarida (which 
see), including the true mites, as the cheese- 
mite, Acarus domesticus. See Acarus and 
cheese-mite. 
acaiidan (a-kar'i-dan), a. and n. I. a. Of or 
belonging to the Acarida or Acaridce. 
H. n. One of the Acarida. 
Acaridea (ak-a-rid'e-a), n. pi. [NL., < Acarus 
+-id-ea.] Same as Acarida. 
Acarina (ak-a-ri'na), n. pi. [NL., < Acarus + 
-ina.] Same as Acarida. 
acarinosis (a-kar-i-no'sis), n. [NL., < Acarina 
+ -osis] A disease, as scabies, produced by 
the presence of a parasite belonging to the 
Acarida, or mites. 
acaroid (ak'a-roid), a. and n. [< NL. Acarus, 
q. v., + -aid] I. a. Of or pertaining to the 
Acarida; resembling the mites; mite-like. 
Acaroid gum, a red resin that exudes from the trunks of 
the Australian grass-tree, Xaitthorrhata hastiiis, and other 
species. Also called Botany Bay resin. Acaroid resin. 
Same as acaroid yum. 
II. n. One of the Acarida; a mite. 
acarpelous (a-kar'pe-lus), a. [< Gr. a- priv. 
+ carpel + -ous.] In bot., having no carpels. 
Syd. Hoc. Lex. 
acarpous (a-kar'pus), a. [< Gr. ikaproc, with- 
out fruit, < a- priv. + /tapmif, fruit : see carpel.] 
In bot., not producing fruit ; sterile ; barren. 
Acarus (ak'a-rus), n. [NL., < Gr. aicapi, a kind 
of mite bred in wax, < dxap^c, short, small, tiny ; 
prop, of hair, too short to be cut, < o- priv. 
+ Keipeiv, cut, orig. "aKtipuv = E. shear, q. v.] 
1. The typical genus of the family Acarida;, or 
true mites. 2. [I. c] A tick or mite, without 
regard to its genus. [In this sense it may 
have a plural form, acari (ak'a-ri).] 
The acanis (Myobia coarctata) of the mouse. 
Huxley, Auat. Invert., p. 331. 
acastt (a-kasf), '. *. [< ME. acasten, akasten, 
pp. acast, akast, throw away, cast down, < a- 1 
+ casten, cast : see cast 1 .] To cast down; cast 
off; cast away. 
acatalectic (a-kat-a-lek'tik), a. and n. [< L. 
acatalecticus, also dcatalectus, < Gr. aK 
not stopping, < a- priv. + "/cora^/croc, K 
/if, leaving off, stopping: see catalectic.] I. a. 
In pros., not halting short: complete; having 
A Tick (fxo&j fiffmts, female), il- 
lustrating structure of Acarida. 
a, nuindibular booklets ; c. hook- 
lets of sternal surface of proboscis ; 
b, d, f. fourth, third, antl second joints 
of the palp ; /, base of the suctorial 
proboscis ; g, stigma ; h, genital 
aperture ; t, anal valves. 
