dictyoxylon 
The leaf-scars of dictyoxylon are subpcntagonal in form, 
broader than they are long, and have a slight groove at 
the upper end. 
dicyan, dicyanogen (di-si'an, dl-sl-an o-jen), 
n. [< di-' 2 + cyan(ugen).] See cyanogen. 
Dicyema (dis-i-e'ma), n. [NL., < Gr. &-, two-, 
i an embryo, a fetus, < nwiv, be preg- 
1604 
is composed of two cysts : contrasted with Mo- 
nocystidea. 
did (did). Preterit of do*, (to 2 . 
didactic (di-dak'tik), a. and n. [= P. didac- 
tiqu-e = Sp. diddctico = Pg. didactico (of. D. di- 
dactisch, a., didactiek, n., = G. didaetisch, a., 
didactik, n., = Dan. Sw. didaktisk, a.), < Gr. 
parasites found in the renal organs of cepha- 
lopods. The body consists of an elongated axial cell 
extending from one end to the other, invested in a single 
layer of comparatively small, 'fattened, nucleated, and 
ciliated cortical cells arranged like a pavement epithe- 
of oiodanEiv, teach (for *rfi-<Sa/c-o-Ki<?), = L. do- 
cere, teach (see docile), cf. disc-ere, learn (see 
disciple) ; cf . Gr. aor. inf. Sarjvai, learn, redupl. 
2d aor. dedae, he taught, perf. Sedartna, also iitiaa, 
I know ; cf . Zend y da, know.] I. a. I. Fitted 
or intended for instruction; containing doc- 
didelphoid 
or for teaching, < tWda/caAof, a teacher, < 6166,- 
oKtiv, teach: see didactic.] Didactic; precep- 
tive; conveying instruction. [Rare.] 
Under what species it may be comprehended, whether 
didascalic or heroic, I leave to the judgment of the crit- 
ics. Prior, Solomon, 1'ref. 
Didascalic syllogism, a demonstrative syllogism. 
didder (did'er), v. i. [E. dial., also dither, < 
ME. dyderen, also dederen, shiver, tremble with 
cold or fear. Another form with the same 
sense is E. dial, dodder, shiver, tremble, shake 
(cf. dial, dadder, confound, perplex), < ME. 
daderen, shiver, etc.; cf. redupl. didder-dod- 
der, tremble; Icel. dadra (Haldorsen), dadhra 
Dicyema tyfus, highly magnified. 
I. Adult, showing large papilla; of Ihe cortical layer and germs in 
interior of axial cell. II. Vermiform embryo in different stages of de- 
velopment. III. Infusoriform embryo: /, the urni fa, its capsule; 
s , its lid ; i, multinucleate cells in its interior. 
Hum around the axial cell, the anterior of these, or polar 
cells, being distinguished from the succeeding or parapo- 
lar cells. The organism is a simple cell-aggregate, with- 
out connective, muscular, or nervous tissues. Reproduc- 
tion takes place by the formation of germs on the axial 
cell. The embryos are of two different kinds, vermiform 
and Infusoriform, whence the name. Those Dieyemida 
which give rise to the former kind are termed Nemato- 
ffena, the others Rhowbogena. 
Dieyemida (dis-i-em'i-da), n.pl. [NL., < Dicy- 
ema + -ida.] A division of animals proposed 
to be established by E. Van Beneden for the 
genus Dicyema, which has no mesoblastic layer, 
' therefore regarded as intermediate be- 
tise; didactic poetry. 
Plato himself, in two of his Dialogues, had used the 
Carthaginian voyages as materials for didactic fiction. 
C. Elton, Origins of Eng. Hist., p. 81. 
2. Pertaining to instruction; of an edifying 
quality, character, or manner; used in or given 
to exposition: as, a didactic style; didactic 
methods; a didactic lecturer. 
Deep obligations lie upon you, . . . not only to be 
blameless, but to be didactic in your lives. 
Jer. Taylor, Works, III. x. 
We . . . shall have our lightest pleasures commented 
upon by didactic dullness. Goldsmith, The Bee, No. 1. 
II. . A treatise on education. Milton. 
didactical (di-dak'ti-kal), a. [< didactic + -al.] 
Same as didactic. [Rare.] 
We shall not need here to describe, out of their didac- 
tical writings, what kind of prayers, and what causes of 
confidence they teach towards the Blessed Virgin Mary 
and all the Saints. Jer. Taylor, Diss. from Popery, I. ii. 9. 
didactically (di-dak'ti-kal-i), adv. In a didac- 
tic manner; in the form of instruction. 
Points best resolved by the books of the Fathers, writ- 
ten dogmatically or didactically. 
Bp. Andrews, Ans. to Cardinal Perron, p. 50. 
Skull of Dicynodon lacerticeps, 
left side. 
Dicyema + -idte.] Same as Dieyemida. 
Dicynodon (d!-sin'o-don), n. [NL., < Gr. Si-, 
two-, + KVUV (KW-), 
dog (= E. hound), 
+ Moiif (MovT-) = E. 
tooth.] The typical 
genus of Dicynodon- 
cies have been found in 
southern Africa, in the 
Ural mountains, and in 
India, in strata supposed 
to be of Triassic age. 
dicynodont (di-sin'- 
o-dont), a. and n. I. a. Pertaining to the Di- 
cynodontia: as, a dicynodont dentition; a dicyn- 
odont reptile. 
II. n. A member of the Dicynodontia. 
Only the crocodiles now show a like extent of ossifica- 
tion of the occiput, and only the chelonians the trenchant 
toothless mandible. ... In mammals alone do we find a 
development of tusks like that in the dicynodonts. 
Owen, Anat.,I. 161. 
Dicynodontia (di-sin-o-don'shi-a), n. pi. [NL., 
pi. of dicynodon(t-) : see Dicynodon.] 1. An 
order of extinct reptiles, probably of the Tri- 
assic period, remains of which have been found 
in Asia and Africa: a synonym of Anomodontia. 
crocodilian vertebra), four or five of which form a sacrum ; 
with a massive skull, lacertilian in most of its charac- 
ters, but with chelonian jaws, which were doubtless in- 
cased in a horny beak ; and as a rule with two great tusks, 
one on each side of the upper jaw, deeply socketed in the 
maxilla, and growing from persistent pulps. 
2. A family or subordinal group of Anomodon- 
tia : same as Dicynodontidte. 
dicynodontian (dl-sin-o-don'ti-an), a. and n. 
I. a. Of or pertaining to the Dicynodontia. 
The supposition that the Dinosaurian, Crocodilian, Di- 
cynodontmn, and Plesiosaurian types were suddenly cre- 
ated at the end of the Permian epoch may be dismissed, 
without further consideration, as a monstrous and un- 
warranted assumption. 
Huxley, Critiques and Addresses, p. 213. 
II. n. One of the Dicynodontia. 
dicynodontid (di-sin-o-don'tid), n. A member 
of the IHeyitodoiitidte. 
Dicynodontidse (di-sin-o-don'ti-de), n. pi. 
[NL., < Dicynodon(t-) + '-idee.'] A family of 
fossil reptiles, typified by the genus Dicynodon. 
Dicystidae (dl-sis'ti-de), n. pi. [NL., < Dicy- 
stis (< Gr. 61-, two-, + KVOTIC,, bladder, mod. 
'cyst'), the typical genus, + -ida;.] Same as 
Gregarinidw. 
Dieystidea (di-sis-tid'e-a), n. pi. [NL., < Dicy- 
stis (see Divystida;) -f- -ideaT] A division of 
Gregarinida containing those in which the body 
to convey instruction ; one who writes didac- 
tically. 
His essays are illuminated by his poetic imagination, 
and he thus becomes a better prose-writer than a mere 
didactician ever could be. Stedman, Viet. Poets, p. 100. 
didacticism (di-dak'ti-sizm), n. [< didactic + 
-ism.] The practice of conveying or of aiming 
-' " - ^- tendency to be di- 
See diddle 1 and daddle.] To shake; tremble; 
shiver with or as with cold. Sherwood. 
He did cast a squinting look upon Goatsnose diddering 
and shivering his chaps. Urquhart, tr. of Rabelais, iii. 20. 
diddest (did'est). A rare and nearly obsolete 
form of didst. 
diddle 1 (did'l), r. i. ; pret. and pp. diddled, ppr. 
diddling. [A var. of didder, the freq. suffixes 
-er and -le being interchangeable. Cf. daddle, 
and dadder mentioned under didder.] To tod- 
dle, as a child in walking; move rapidly up 
and down, or backward and forward; jog; 
shake. [Prov. Eng. and Scotch.] 
And when his forward strength began to bloom, 
To see him diddle up and down the room ! 
0, who would think so sweet a babe as this 
Should e'er be slain by a false-hearted kiss? 
Quarles, Divine Fancies, t 4. 
Lang may your elbuck jink an' diddle. 
Burns, Second Epistle to Davie. 
diddle 2 (did'l), v. t. ; pret. and pp. diddled, ppr. 
diddling. [A slang word, of obscure origin; 
perhaps < diddle 1 , though the connection is not 
obvious. A connection with AS. dyderian, be- 
dyderian, deceive, delude, is possible, but ME. 
forms are lacking.] To cheat; overreach by 
deception; swindle. [Slang.] 
I should absolutely have diddled Hounslow if it had 
not been for her confounded pretty face flitting about my 
stupid brain. Disraeli, Young Duke, ii. 3. 
diddler (did'ler), n. [< diddle* + -eri.] A 
cheat; a swindler. [Slang.] 
didet. A Middle English form of did. See do 1 . 
didecahedral (di-dek-a-he'dral), a. [< di-2 + 
decahedral.] In crystal., having the form of a 
That contemplative method which rose to imagination 
in the high discourse of Wordsworth . . . too often sinks 
to didacticism in the perplexed and timorous strains of 
his disciples. Stedman, Viet. Poets, p. 413. 
didacticity (did-ak-tis'i-ti), n. [< didactic + 
-ity.] The quality of being didactic ; didacti- 
cism. Sure. [Rare.] 
didactics (di-dak'tiks), n. [PI. of didactic: see 
-ics.] The art or science of teaching; peda- 
gogics. 
lidactiye (di-dak'tiv), a. [< didact-ic + -ive.] 
Didactic. [Rare.] 
He is under the restraint of a formal or didactive hy- 
pocrisy. Lamb, Old and New Schoolmaster. 
didactyl, didactyle (di-dak'til), a. and n. [< 
Gr. <5TdTt>/lof, two fingers long or broad, lit. 
having two fingers, < 01-, two-, + <5dicrt>/lof, fin- 
ger: see dactyl.] I. a. Having only two digits, 
as fingers or toes; two-fingered or two-toed: 
in the arthropods, applied to limbs which ter- 
minate in a forceps or chela. Also bidactyl. 
II. . An animal having two toes only on 
each foot, as the Bradypus didactylus or two- 
toed sloth. 
didactylous (di-dak'ti-lus), a. [As didactyl + 
-ous.] Same as didactyl. 
didapper (did'ap-er), n. [Also diedapper, di- 
dopper (also in restored forms divedapper, dive- 
dopper), < ME. "didopper, dydoppar, the same, 
with suffix of agent -er 1 , as the older *dtie- 
doppe, devedoppe, dyvedap, used by Wyclif (as 
dippere, i. e., dipper, by Purvey) to translate L. 
mergulus in Deut. xiv. 17 and Lev. xi. 17 (where 
the A. V. , and also the R. V. , has " pelican " and 
" cormorant ") ; < AS. dufedoppa, a general term 
for a diving bird (used to translate L. pelicanus, 
pelican), < dufan, dive, + doppettan, dop, dip : 
see dive, dop, dopper, dip, dipper, dabchick.] 1. 
The dabchick or little grebe of Europe, Podici- 
pes or Sylbeocyclus minor. 2. One of sundry 
other small grebes, as the pied-billed dabchick, 
Podilym bus podicipes. 
didascalar (di-das'ka-lar), a. [As didascal-ic 
+ -ar.] Same as didascalic. Bulwer. [Rare.] 
didascalic (did-as-kal'ik), a. [= Sp. didasca- 
lisco = Pg. It. didasealico, < Gr. Aoao/ca/Uxof, of 
didelph (di'delf), . A member of the 
phia ; a marsupial. 
Didelphia (di-del'fi-a), n. pi. [NL., < Gr. it-, 
two-, + detyvc, womb. Cf. Didelphys.] The 
Marsupialia or marsupial implacental mam- 
mals; one of the three subclasses of Mamma- 
lia, the other two being Ornithodelphia and 
Monodelphia. They have no placenta, and the womb 
double, whence the name that is, the uterine dilatations 
of the oviducts continue through life distinct from each 
other, right and left, and open into two distinct vagi- 
nae, which debouch in turn into a urogenital sinus, form- 
ing, with the termination of the rectum, a common clo- 
aca embraced by the external sphincter muscle, and in 
the male lodging the penis, which thus appears to pro- 
trude from the anus. The female has usually an abdomi- 
nal pouch or marsupium, formed by a fold of the skin of 
the belly, in which the mammary glands open, and into 
which the blind, naked, and imperfectly developed young 
sition. Both the marsupium and the scrotum are sup- 
ported to some extent by the marsupial bones character- 
istic of this group, being ossifications in the tendon of the 
external oblique muscle of the abdomen, articulated with 
the pubes. A cremastcrie muscle in relation with these 
bones acts in the female upon the mammary glands, ef- 
fecting their compression, and consequently the How of 
milk into the mouths of the helpless young. There are 
true teeth of two or three kinds. The coracoid is reduced 
to a process of the scapula, as in ordinary mammals, not 
reaching the sternum, as in monotremes. The corpus 
callosum is rudimentary or wanting, and the brain rela- 
tively small. The Didelphia are among the oldest known 
mammals, and formerly had an extensive range, but are 
now mainly confined to the Australian region, the Amer- 
ican opossums offering the principal exception. Some of 
the extinct forms were of great size ; the kangaroos are 
the largest living representatives. The marsupials are 
notable for their great physiological adaptation to all the 
modes of life of ordinary mammals, their structure being 
modified in relation to the carnivorous, the herbivorous, 
the rodent, and other habitudes, and their modes of pro- 
gression and general economy being no less diverse. There 
is luit one order, llammalut (which see). 
didelphian, didelphic (di-del'fi-an, -fik), a. [< 
Didelphia + -an, -ic.] Pertaining to or having 
the characters of the Didelphia. 
didelphid (dl-del'fid), . A member of the Di- 
dvli>lna; especially, one of the Dide!phi/ida'. 
Didelphidae, n. pi. [NL.] See Didelph ijida'. 
didelphoid (di-del'foid), a. [< Didelphia + -aid.] 
Double, as the uterus in the subclass Didelphia, 
