Placoidea 
Placoidea (plii-koi'de-ji), n. pi. [NL.] Same 
as riili'itiilri. 
placoidean (pla-koi'de-an), a. and n. [< placoid 
+ -< j -ini. } Same as iil'icoid. 
Placoidei (pla-koi'de-i), . pi. [NL. : see olii- 
roid.] In Agassi/.'s classification, an artificial 
group of fishes, having placoid scales: corre- 
lated with t'tcnoidci, Cycloidd, and (laitoitlei. It 
is mainly equivalent to the class Eltwmobraiichii, 
but also included the naked marsipobranehs. 
placoidian(pla-koi'di-an),i. [<. placoid + -ian.] 
Same as placoid. 
Placophora (pla-kof'6-rfi), n. pi. [NL., < Gr. 
-'/ui; (Tr'/.aii-), a tablet, plate, + ffpeiv = 'E. bear 1 .] 
In Gegenbanr's system of classification, one of 
two primary divisions of the Mollusca, consist- 
ing of the chitons only. The Polyplacophiira and 
Amphiniitra of Lankester, though of a very different taxo- 
nomic grade, are conterminous. See Polyplacitphora, and 
cut under Chitonidx. 
placophoran (pla-kof'6-ran), a. and n. [< pla- 
i-ophor-uux + -an.] I. a. Placophorous; be- 
longing to the Placophora. 
II. H. AmemberaxthePtMOptara; a chiton. 
placophorous (pla-kof'o-rus), a. [< (Jr. irAdf 
(-/UK-), a tablet, 'platej + flptw = E. bear*-.] 
Same as placophoran. 
placula ( plak'u-lii), M. ; pi. placulx (-le). [NL., 
dim., < Gr. Tr/fd^' (irfatu-), a tablet, plate.] A 
little plate or plaque: specifically applied to 
certain discoidal embryos consisting of a mass 
of cleavage-cells disposed as a plate or layer: 
see monoplacula and diploplacula. Hyatt, Proc. 
Bost. Soc. Nat. Hist., 1884, p. 97. 
placular (plak'u-liiv), a. [< placula + -ar 8 .] 
Plate-like; flat and broad; having the charac- 
ter of a placula. 
placulate (plak'u-lat), a. [< placula + -ate*.] 
Having the form of a placula ; being a placula 
or in the placular stage of development, as an 
embryo. 
Placuna (pla-ku'nji), n. [NL. (Bruguiere, 
1792), < Gr. 7r/df (jr/oV), a tablet, plate.] The 
typical genus of Placmiidee. They have thin, more 
Saddle bliell ^Plactma srlla). 
or less translucent shells, which are nearly equivalve, and 
t Indian seas. P. 
no byssus. .Several species inhabit East 
flacenla Is known as the vindi>w-hdl, P. fella as the 
Mitdle-sheU. 
Placunidae (pla-ku'ni-de), n. pi. [NL., < Pla- 
CIIHII + -idle.] ' A family of bivalve mollusks, 
typified by the genus Placnna, whose species 
are generally associated in the same family 
with the typical Anomiidte, and are known as 
iriiidoir-sliellii, window-oysters, and saddle-shells. 
pladarosis (plad-a-ro'sis), n. [NL., < Gr. Tr/tada- 
povatiai, become soft and flabby, < ir^aAapoc, wet, 
damp, flaccid, flabby, < xhafiav, be flaccid.] A 
soft tumor or wart on the eyelid. Also plada- 
rotis and pl(nlaroma. 
plafond (pla-foud'), H. [= Sp. plafon; < P. 
plafond, ceiling, < plat, flat (see plate), + fond, 
bottom: see/and 1 , /ownd 2 .] In areli., the ceil- 
ing of a room, whether flat or arched ; also, the 
under side of the projection of the larmier of a 
cornice, and generally any soffit. A\$oplatfond. 
plaga (pla'ga), .; pi. plat/a (-je). [NL., < 
L. plaga, a blow, stroke, wound, stripe: see 
/I/ague.] In ~~<'7., a stripe or streak of color. 
Plaga scapularis, In entmn., same as jwrapsw'. 
Haliiltnl. 
plagal (pli'ggl). a. [= P. ptagal = It. pJaoale, 
< ML. phzoitM, < Gr. TrAayiof, sidewise, slanting. 
athwart, oblique, < irl.ayof, ;r?a}oc, side.] 1. In 
tinyoi-iiiii music, noting a mode or melody in 
which the final is in the middle of the compass 
instead of at the bottom: opposed to authentic. 
See mode 1 , 7. 2. In modern mimic, noting a ca- 
dence in which the chord of the tonic is pre- 
ceded by that of the subdominant. See nidi << . 
4523 
plagardt, Same as placard, 4, for placcalr. 
plagate (pla'gat), . [<;/</ + -air 1 .'] Striped 
or streaked. 
plage't, n. A Middle English form of )</</'"'. 
plage-r (plaj), . [< ME. /./<//. < OF. //</ 
(also plate), P. plage = 8p. Pg. It. plaga, < L. 
plaija, region, quarter, tract. Cf. Gr. irxa^-, the 
side: see plagal.] 1. A region; a district. 
Alle Crlsten folk ben fled fro that contree 
Thurgh payens, that conquereden al aboute 
The pltujet of the North by land and see. 
Chaucer, Man of Law's T>le, 1. 445. 
As far as from the frozen plage of heaven 
Unto the watery morning s ruddy bower. 
Marlowe, Tambuilalne, I.. IT. 4. 
2. Quarter of the compass. 
Now hastuw her the foure quarters of thin astrelable, 
devyded after the foure principals ptaye* or quarters of I he 
firmament. Chaucer, Astrolabe, i. 6. 
Plagianthus (plaj-i-an'thus), n. [NL. (J. and 
G. Forster, 1776), < Gr. ;r/<j)<or, oblique, + ar- 
60$, flower.] A genus of polypetalous shrubs 
of the order Malraee and the tribe Malvea-, un- 
like the other genera of its subtribe Sidcx in its 
longitudinally stigmatose style-branches, and 
characterized by a five-cleft calyx, distant or 
obsolete bracteoles, many-cleft stamen-column, 
and one, two, or many carpels, each with one 
pendulous seed. There are 11 species, all natives of 
Australia and New Zealand. They bear alternate or clus- 
tered, usually entire or angled leaves, and polygamous red, 
whitish, or yellowish flowers, usually small and densely 
crowded in the axils or in a terminal spike. Several low 
shrubby species produce a useful fiber. (See hemp bush and 
currajony.) I', tetulinui, the ribbon-tree of Utago, New 
Zealand, also called cotton-tree, lacebark, and akaroo-tree, is 
an evergreen reaching sometimes 70 feet, though usually a 
tangled bush, and yields a very tine tough tlber resem- 
bling mix, derived from the inner Iwrk of the young 
branches. 
plagiarise, ' Not> plaiiiarix. 
plagiarism (pla'p-a-rizm), n. [= Pg. plaqia- 
rixmo; as pltiffiar-y"+ -ixm.] 1. The purloining 
or wrongful appropriation of another's ideas, 
writings, artistic designs, etc.. and giving theso 
forth as one's own; specifically, the offense of 
taking passages from another's compositions, 
and publishing them, either word for word or 
in substance, as one's own; literary theft. 
Sir J. Reynolds has been accused of plairiarimn fur hav- 
ing iHirrowed attitudes from ancient masters. Not only 
candour but criticism must deny the force of the charge. 
Walpole, Anecdotes of fainting, IV., adv. p. vii., note. 
2. A passage or thought thus stolen. 
plagiarist (pla'ji-a-rist), H. (<pl(iniar-i/ + -is/.] 
One who plagiarizes: one who is guilty of pla- 
giarism. 
You glean from the refuse of obscure volumes, where 
more judicious plaijiarirtf have been before you ; so that 
the body of your work is a composition of dregs and sedi- 
mentslike a bad tavern's worst wine. 
Slirridan, The Critic, i. 1. 
plagiarize (pla'ji-a-riz), r.; pret. and pp. plagi- 
arized, ppr. plagiarising. [< plagiar-y + -i:e.] 
1. trans. To steal or purloin from the writings 
or ideas of another: as, to plagiarize a passage. 
II. iiitranx. To commit plagiarism. 
Also spelled plagiarise. 
plagiary (pla'ji-a-ri), n. and a. [Formerly pla- 
uiarie; < F. plagiaire = Sp. Pg. It. plagiario, a 
kidnapper, a plagiarist. < L. plagiarius, a kid- 
napper, plagiarist, < (LL.) plagium, kidnap- 
ping, prob. < plaga, a net. snare, trap, prob. 
orig. "placa, < plec-t-ere = Gr. irMiieiv, weave: 
see plait.] I. .; pi. plagiaries (-riz). If. A 
manstealer; a kidnapper. 
He was a Cyrenean by birth, and ... In the time of his 
minoritie or child hood he was by some Playiary stolne 
away from his friends, and sold to the Ismaelite Mer- 
chants. Purcha*, Pilgrimage, p. 243. 
2. A plagiarist. 
Why the ditty 's all borrowed ; 'tis Horace's ; hang him, 
plagiary! B. Jonsoit, Poetanter, iv. 1. 
3. The crime of literary theft ; plagiarism. 
Plaaiarie had not Its nativitie with printing, but began 
In times when thefts were difficult, and the paucity of 
bookes scarce wanted that invention. 
Sir T. Brmrne, Vulg. Err., i. 6. 
II. a. It. Manstealing; kidnapping. 
Plagiostoma 
merly referred to the marsupials, but by recent writers I* 
generally relegated to the Piutulhrria, us a representative 
of a peculiar order, JHvltittilirrcHltita. Kemains referred 
to this family m-cnr in Kunipe and America, ranging 111 
geologic time from the Triaaaic to the Eocene. 
Plagiaulax n.ln-ji-a'laks), H. [NL., < Gr. wld- 
;/of, oblique, + avtof, furrow.] A genus of fos- 
sil primitive mammals from the Purbeck beds 
of the Upper Oolite, as /'. In-cclt-xi, I', minor, and 
others. 8ee diprotodotit, polyjirotodont. 
plagihedral (pla-ji-he'dral), a. [= P. plagi- 
etlre, < Gr. irX<i)/ar, oblique, 4- in/a, seat, batte.] 
In crysUil., haying faces obliquely arranged, as 
in certain hemihedral forms whicn are euantio- 
morphous to their complementary forms that 
is. related to them as a right glove is to the left : 
this is true of the trapezohedral planes on a 
quartz crystal. 
plagiocephalic (pla'ji-o-se-fal'ik or -sef'a-lik), 
. [< plagioct-plial-oim + -4e.] 1. Having a 
broad head with flattened forehead. Jour. An- 
ihrop. Just., III. 90. 2. Pertaining to or ex- 
hibiting plagiocephaly. 
plagiocephalous <pla*ji-o-sef'a-lus), a. [< Gr. 
Tr/ujyiof, oblique, + (^a>/>, head.] Same &spla- 
aincejihalie, 1. 
plagiocephaly (pla'ji-o-sef'a-li), . [< pla,/io- 
cephal-ous + -y.] Oblique deformity of the 
skull, such that the anterior part of one half 
is more developed, and similarly the posterior 
part of the other half. 
plagiocitrite (pla'ji-o-sit'rit), n. [< Gr. ir/l<i)/f, 
oblique, -t- L. citrus, citrus (see citrus), + -iUV.] 
A hydrous sulphate of iron, aluminium, sodi- 
um, and potassium, occurring in fibrous crys- 
talline forms of a lemon-yellow color near 
Bischofsheim vor der Rhon, in Bavaria, 
plagioclase (pla'ji-o-klaz), u. [< Gr. irZa-yior, 
obuque. + k'/aaif, fracture, < K/OI>, break.] The 
name given by Breithaupt to the group of tri- 
clinic feldspars the two prominent cleavage- 
directions in which are oblique to each other. 
The plagioclase-feldspar group includes alhitc, anurthite, 
and the intermediate species, oligoclaw, andefiin, labr- 
dorlte: with these the triclinlc potash feldspar inlcrocline 
Is sometimes included. See/rfp<ir. 
plagioclastic (pla'ji-o-klas'tik), a. [< (ir. TT/IIJ- 
vof, oblique, + xXaoroc, broken; of. rlantir.] 
Breaking obliquely ; characterized by two dif- 
ferent cleavages in directions oblique to one an- 
other, or pertaining to a mineral (as one of the 
triclinic feldspars) which has this property. 
Plagiodon (pla-ji'o-don), H. [NL. (orig. Plagio- 
tliHitia, F. Cnvier,' 1836), < Tr^iiyiof, oblique, + 
oov>i''f (oiSoiT-) = E. tooth.] 1. A West Indian 
genus of small hystricomorphic rodents of the 
family Octodontidfe and subfamily Ecliinomy- 
Plagiary and man-stealing Tartar*. 
Brmm, Travels (1686X p. 49. (Latham.) 
2. Practising literary theft. 
Or a Hos ego from old Petrarch's spright 
Unto a vlainaru sonnet-wright. 
Bp. UaU, Satires, IV. II. 84. 
Plagiaulacidae (pla'ji-a-las'i-de), n. pi. [NL., 
< I'liiijiiiiiliij- (-In/'-) + -idfe.] A widely distrib- 
uted family of fossil mammals, typified by the 
genus Plagiaulaf. The premolars were obliquely 
grooved and' the last was enlarged, the true molais t.. 
on each side and small, and the incisors of the lower pw 
inclined forward and two in number. The family was for- 
inte : so called from the diagonal grooves of the 
molars. The molars are rootless ; the thumb is rudi- 
mentary: the tail Is short and scaly ; the fur Is coarse, with 
silky under-fur : the muzzle Is blunt ; and the whole form 
Is stout. The genus Is closely related to Cavrotnyi. There 
is only one species, /'. jrdium at San Domingo. 
2. A genus of reptiles. Ditmerti. 3. A genus 
of mollusks. Isaac. Lea. 
plagiodont (pla'ji-6-dont), a. [< Gr. n-Xdj-iof, 
oblique, + iio6( (o<W-) = E. tooth.] Having 
the teeth oblique: noting the dentition of ser- 
pents whose teeth are like one another, those of 
the palate being set in two converging series. 
Plagiodus (pla-ji-6'dus), . [NL. (orig. PUii/i/n- 
dnx, Steller, 1811): see Plagiodw.] Same as 
.llrpidoxaiirug. See cut under handxaw-Jish. 
plagionite (pla'ji-6-nit), n. [< Gr. wXayiof, 
obfique, + -H- + -ite-.] A snlphid of antimony 
and lead, occurring in oblique monoclinic crys- 
tals and in massive forms. It has a dark lead- 
i:ray color and metallic luster. 
Plagiostoma 1 (pla-ji-os'to-mii), n. [NL. (Sow- 
erby, 181'J). fern, sing.: see plagiostome.] A 
gnnj of bivalve mollusks of the family l.imi- 
iln . or a subgenus of Lima, containing such 
species as P. cardiiformis. See cut under 
l.imii. 
