diplanetism 
being twice active, with an intervening period 
of rest. It occur* in (In- /ooMiorrs of certain genera of 
tiiiiirnlf'liiinr, in which tin- /o,,,p, n V, escape without cilia 
frniii the .sporangium. iiml come to rest in a duster, each 
funning :l cell "all. After some hours of rest tin- pn.li. 
plas ..... f eacli >po]v i 'M'apeH fnilll its cell-wall, ill-quires 
rtli.i, all'l enters upon iv period of active movement. 
diplantidian(dip-lan-tid'i-an),. [<Gr.''(ir?.<ior, 
(lonl>l(>, + HIT/, against, + clAof, form, image.] 
Showing two images, one reversed and the 
other direct: applied to a telescope proposed 
in 1778 by Jeaurat, to be lined in taking tran- 
sits, the coincidence of the two images serving 
in place <if a transit over an illuminated wire. 
The difficulties of the execution of such an Instrument are, 
however, far greater than those of Illuminating a wire. 
Diplarthra (dip-lar'tin-ii), >/. />!. [NL/., nout. pi. 
ofdiplarllirms: see itiplt'irtliroH.t.'] Diplarthrous 
mammals; those hoofed quadrupeds which ex- 
hibit or are characterized by diplarthrism. 
They arc the artiodactyls ami the perissodact.vls, or the 
I'lvitilnta in a proper restricted sense, collectively distin- 
guished from the rOMMOdl (which see). 
diplarthrism (dip-liir'thrizm), n. [< <li/>l<n-- 
tlir-om + -ism.'] The quality or condition of be- 
ing diplarthrous ; the alternation of the several 
bones of one row of carpals or tarsals with those 
of the other row respectively, instead of that 
linear arrangement of the respective bones of 
both rows which constitutes taxeopody (which 
see) : so called because each bone of one row 
interlocks with two bones of the other row. 
Hftin appears in that foot before it does In the 
fore foot, as ill the. 1'robosciilia. 
K. 1). Cope, Amer. Nat., .\ \ 1 MS, 
diplarthrous (dip-lar'thrus), a. [< NL. diplar- 
tliniK, < Gr. <5<7r/ioof, double, + apff/iov, joint.] 
Doubly articulated, as a bone of one row of car- 
pal or tarsal bones with two bones of the other 
row; characterized by or exhibiting diplar- 
thrism; not taxeopodous : as, a diplarthrous car- 
pus or tarsus ; a diplarthrous ungulate mammal . 
The conversion of a taxeopod Into a diplarthrrm* ungu- 
late. K. D. Cope, Amer. .Nat., XXI. 988. 
diplasiasmus (di-plil-si-as'mus), H. [NL., < Gr. 
Atir'/.amaa[i6f, a doubling, as of a letter or word, 
< inrfaioidfciv, double, < AnrXaaiof, double : see 
diplasic.'] 1. A figure of orthography, consist- 
ing in writing a letter double which is usually 
written single, as, in Greek ToarsAg for roauf. 
2. In rhet., repetition of a word or name for 
the sake of emphasis: as, "O Jerusalem, Jrra- 
Kiilem, thou that killest the prophets," Mat. 
xxiii. 37. Also called epi-euxis. 
diplasic (di-plas'ik), a. [< Gr. Am^daioc, double, 
< fit-, two-, + -ir)iaaioc, -fold, connected with 
-7r?,oof, and nit. with E. full 1 , -fold.] Double ; 
twofold; specifically, in owe. pros., constitut- 
ing the proportion of two to one : as, the di- 
/iluxic ratio (of thesis and arsis); character- 
ized by such a proportion of thesis and arsis: 
as, diplasic rhythm ; a diplasic foot ; the dipktsic 
class (of feet). The diplaalc class of feet comprises 
those feet in which the thesis or metrically accented part 
(called by many the arsis) has double the length of the 
arsis or metrically unaccented part (called by many the 
thesis). The diplasic feet are (1) the trisemlc feet (equal 
to < ^ | w or <* | t "), the trihrach, trochee, and iambus, 
and (2) the hexasemic feet (equal to^www|~worww| 
~ ^ ^ _i the Ionic a majore, the Ionic a miuore, Molog- 
sus, and choriamb. 
The diplasic ratio answers to our common time. 
J. Hartley, Essays, p. US. 
diplasion (di-pla'si-ou), n. [< Gr. AmUaiov, 
neut. of (W/'.acfrof, double: see diplaxic.] 1. In 
inn: dr. music, a triple rhythm in which there 
was an alternation of tones whose durations 
were as two and one respectively. 2. 1 
dici'iil miixii; the interval of an octave. See 
diapiifnu. 3f. A form of pianoforte with two 
keyboards, used in the eighteenth century. 
Dip'lax (di'plaks), H. [NL., < Gr. <!<V?^zf, two- 
fold, < At-, two-, + --/.of, -fold; cf. diplasic.] 
1. In entom., a genus of dragon-flies, of the 
family Libellnlidie. 2. A genus of rotifers or 
wheel-animalcules. 1'. H. Goxxe. 
diple (di'ple), . [< Gr. ilur?.?/, a critical mark 
(as in def.), prop. fern, of <!/TAoi>o, coutr. form of 
o/T?^Sr, double : see diploe. "\ In palcoij., a criti- 
cal mark like a T or A laid on its side (i-, >), 
used as a mark of a paragraph, the change 
from one speaker to another in a drama, dif- 
ferent readings, rejection of a reading, etc. 
diplegia (di-ple'ji-ii), n. [NL., < Gr. <!/-, two-, 
+ T/;/; /,. a stroke.] In pathnl., paralysis of cor- 
responding parts on the two sides of the body. 
as of the two anus or of the two sides of the 
face. 
diplegic (di-plej'ik), it. [< dipleyia + -.] Per- 
taining to or of the nature of diplegia Diplegic 
1631 
contractions, contractions which, when the anode of a 
It.ilvanle rurrant In applinl I" Hie inastoid pr ...... vs and 
tin' laiL-i- cath"<lc i- p]:iccil IM I\M. ( ii tin- shoulder-blades, 
ha\e iii some ca.-cs IT, n scon in the muscles of ttie arm 
on the Mile opposite that to v. hi- h tlie anode is applied. 
dipleidoscope (di-plj'do-skop), . [Irreg. < Or. 
I|;T/W, double, -f- elf of, appearance, + anoireiv, 
view.] An instrument for indicating the pas- 
sage of the sun or a star over the meridian liy 
the coincidence of two images of the object, 
the one formed by single and the other by 
double reflection. It consists of an equilateral hollow 
prism, two of whose sides are silvered on the inside so as 
to be mirrors, while the third Is formed of glass. The prism 
is adjusted no thai om of the silvered sides shall lie exactly 
In the plane of the meridian, mill the transparent side 
toward the object. So long as tlie object has notreachc,! 
the meridian, tlie linage produce,! by that portion nf the 
rays reflected directly from the glass surface, and that pro- 
iluccit iiy the rays transmitted through the glass to the 
silvered side, reflected (nun It to the other, and thenre 
through the glass, are not eoitieiileut, but gradually ap- 
proach as the sun or star approaches the meridian, until 
they exactly coincide at the instant the center of the ob- 
ject Is on the meridian ; then an eye stationed at the side 
of the prism and looking toward the transparent side sees 
only one object. 
Dipleura (di-plo'r*), . pi. [NL., neut. pi. of 
'iliptrurux, < Gr. A'i-, two-, + irfavpd, side. Cf. 
i/iplfiiric.] In mnrpliiil., those organic forms 
which are dipleural: distinguished from Tetra- 
pleura. 
Haeckel again divides these, according to the number 
of aiitimeres, into Tctrapleura and Dipkura. 
Kneye. Brit., XVI. 844. 
dipleural (di-plo'ral), a. [As diplfur-ic + -at.] 
In Hinrphol., zygopleural with only two anti- 
meres; dipleuric. Haeckel. 
dipleuric (di-pl8'rik), a. [< Gr. At-, two-, + 
trv.evpd, side, + -if.] Being right and left, as 
sides ; having right and left sides ; being sym- 
metrically bilateral, or exhibiting bilateral sym- 
metry. 
Dipleurobranchia (dl-plo-ro-brang'ki-ii), . pi. 
[NL., < Gr. <!<-, two-, + ir'/tvpa, side, +pp6yxia, 
gills.] A superfamily of nudibranchiate gas- 
tropods, having foliaceous branchire situated 
in a fold on each side, and no shell, and con- 
taining the families 2'liyllidiidie and 1'leurophyl- 
lidiida; which are thus contrasted with Mono- 
plettrobranchia. The group is also called /- 
~ferobrancliiata or lli/pobranchiata. 
dipleurobranchiate (di-plo-ro-brang'ki-at), a. 
[< Dipteurobrancliia + -ate 1 ."] Pertaining to or 
having the characters of the Dipleurnbranchiit. 
diplex (di'pleks), a. [< Gr. it-, two-, + L. -plei, 
as in duplex; a distinctive var. of duplex.] 
Double: applied to a method of transmitting 
two messages in the same direction and at the 
same time over a single telegraph-line. 
The terms contraplex and dt'itlex are here applied as 
specific names for designating clearly the way In which the 
particular simultaneous double transmission to which we 
wish to refer is effected. Thus, for instance, two messages 
may le sent over a single wire in the same or in opposite 
directions, and when we do not care to particularize either, 
we simply allude to them under the more common generic 
name of duplex transmission, which includes both. When, 
however, we wish to speak of either method by itself, we 
use the term dijttex for simultaneous transmission in the 
same direction, and contraplex for that In opposite direr- 
lions. O. B. Prtxcott, Elect. Invent., p. 848. 
diplobacteria (dip"16-bak-te'ri-a), n. pi. [NL. , 
< Gr. 6t7r).6of, double, + NL. ^bacteria, pi. of 
bacterium, q. v.] Bacteria which consist of two 
cells or adhere in pairs. 
These diitlo-liartrria may assume a curved or sausage 
shape. Amer. Xal., XXII. 12*. 
diploic 
spicules running in opposite directions, and 
loaned like an hour-glass or a double com'. 
Diploconus (dip-lo-ko'nus), n. [NL., < Gr. 6t- 
-/inii. iloulile. 4- KUWX, cone.] A genus of mono- 
cyttnrian radiolarians, giving name to the fam- 
ily ItipliicoHiilir. llna-kel, 1860. 
diplodal ('lip'lo-dal), a. [< Gr. AtTtifjJof, double, 
+ 6ooc, way, + -a/.] In :oiil., having both 
prosodal and aphodal canals, or canals of en- 
trance and exit, well developed, as a sponge. 
The genus ('Imiidroxin is an example. 
Tills, which from the marked presence of both prnnodal 
and aphodal canals may lie termed the dijtiodal type of 
the Hhgon canal >>teni. . . -urn but rarely. 
II. ./ .w/,r, Encyc. BrlL, XXII. 415. 
Diplodocidae (dip-lo-dos'i-de), n. pi. [NL., < 
Diploiloenn + -iilti:] A family of sauropod dino- 
saurs, formed for the reception of the genus 
Diplodocus (di-plod'o-kus), H. [NL., < Gr. At- 
ir/.6o^, double, + Aoniir, a bearing-beam, main 
beam, any beam or bar.] A genus of sauropod 
dinosaurs, based on remains from the Upper 
Jurassic of Colorado. It Is characterized by a weak 
dentition connncd to the fore part of the jaws, and the 
ranii of the i-' liia straight, not exiianded distally, and 
meeting in the middle line. O. C. Marsh, 1878. 
Diplodontia (dip-lo-don'shia), n.pl. [NL., <Gr. 
(icr/.ooc, double, + snore (O&OVT-) = E. tooth.] In 
Blyth's edition of Cuvier, an order of placental 
Mammalia, consisting of the 1'acliydfrmata, her- 
bivorous Cctacea, Kodcntia, and Ruminantia. of 
Cuvier ; one of two orders constituting Blyth's 
phytophagous type of mammals. [Not in use.] 
diploe (dip'lo-e), n. [NL., < Gr. Am/.or/, fern, of 
6nr'/oof, contr. Amlovc, twofold, double (= L. 
duplus, > ult. E. double, q. v.), < Ai-, two-, -f- 
-Tr/jMf, akin to L. plux, more, an<l E./w// 1 .] 1. 
In aunt., the light spongy substance or open 
cancellated or reticulated structure of bone be- 
diploblastic (dip-lo-blas'tik), a. [< Gr. JnrWor, 
double, + Ji/Mar6q, germ, + -ic.] In biol., hav- 
ing two germinal layers, endoblastic and ecto- 
blastic, or a two-layered blastoderm: correlated 
with monoblastic and triploblwtic. 
A third layer, the mesoblast ormesoderm, otvurs ; hem-e 
these are known as triplohlastic animals, In contradistinc- 
tion to those with only hypoblast and epiblast, which are 
called <ii>>l<Maxtic. Stinnl. Xul. Ilixi., I. xl. 
diplocardlac (dip-16-kiir'di-ak), a. [< Gr. fi- 
irt.6os, double, + aapi\ia = E. heart: see cardiac.] 
Having the heart double that is, with com- 
pletely separated right and left halves, and con- 
sequently distinct pulmonary and systemic cir- 
culation of the blood, as all birds and mammals. 
diplOCOCCUS (dip-lo-kok'us), M. ; pi. dijtloeocci 
(-si). [NL., < Gr. dnr^ooc, double, + <,roo, a 
berry.] In biol., a coupled spherule; a cell or 
similar organism resulting from the process of 
conjugation of two or more cells. 
Coupled spherules are called tliplaeocei. 
',; Pathol. Auat (trans-X i. < 185. 
Diploconidae (dip-lo-kon'i-de), n. pi. [NL., < 
Dipli>ci>iinx + -iiln:"\ A family of acantbarians 
with a shell having in its axis a pair of strong 
Section through the Skull of a Cockatoo (Cafattta galtrtla . 
showing the Diploe filling the space between the inner ami outer wall* 
of the cranium. 
tween the hard dense inner and outer tables of 
the cranial bones. 2. In hot., the parenchyma 
of a leaf, lying between the two epidermal sur- 
faces. Also called meditullinm. [Rare.] 
diploetic (dip-lo-et'ik), <7. [< diploe + (improp.) 
-ftic.] Same as diploic. 
Dinlogangliata (dip-lo-gang-gli-a'ta), M. pi. 
[NL., <Gr. AnrUof, double, + yayyhov, ganglion, 
+ -<ifYi2.] i n Grant's classification, a division 
of animals, partially synonymous with the Ar- 
tictdata of Cuvier, or the modern Artliropoda. 
diplogangliate (dip-lp-gang'gli-at), a. Of or 
pertaining to the VipltHjanglinta. 
diplogenesis (dip-lo-jen'e-sis). n. [NL., < Gr. 
(ScrV-oof, double, + jfvfoif, generation.] In tera- 
tol., the duplication of parts normally single, or 
the production of a double monster. 
diplogenic (dip-16-jen 'ik), a. [< Gr. Ajr?.oor, dou- 
ble, T yfvof, kind, + -if.] Producing two sub- 
stances; partaking of the nature of two bodies. 
Diploglossata (dip'lo-glo-sa'ta), n. pi. [NL., < 
Gr. <5,/tooo, double, + -))uoea, tongue, + -afa 2 .] 
A group of saltatorial orthopterous insects, es- 
tablished for the reception of the genus Hemime- 
1'iix. DC tiaiissure. 
diplograph (dip'lo-graf), M. [< Gr. Am/.6of, dou- 
ble, + ^pafciv, write.] A Swiss writing-appa- 
ratus for the use of the blind, consisting of let- 
tered disks with mechanism to rotate them and 
to bring any letter desired in position to imprint 
it on a sheet of paper placed in the machine. 
It is practically a clumsy form of the type-writer. 
K. H. Knialit.' 
Diplograpsus (dip-lo-grap'sus), H. [NL., < Gr. 
(SorXoof, double, + 'qropnu, standing for grap- 
tolite.'] A genus of Paleozoic graptolites, of 
the family OroffoKMAe, having the cells ar- 
ranged back to back on each side of the axis, 
like the vanes of a feather. They occur in the 
Cambrian and Silurian strata. Also IHplograp- 
t-: ../'('i/, 1847. 
diploic (di-plo'ik), (i. [< diploe + -ic.] Of or per- 
taining to the diploe: as, diploic tissue; riiploie 
