thorax 
post-thorax. The hard crust of each of these segments 
may and normally does consist of a number of pieces or 
individual sclerites, on the dorsal or tergal, on the lateral 
or pleura), and on the ventral or sternal aspects. These 
sclerites are known as tergites, pleurites. and sterilizes; 
they have also other names, and many of the individual 
sclerites have specific designations. Thus, dorsal sclerites 
or parts of each segment may be known as pronotmn, 
mesonotwn, and metanotinn, and so with pleural and ster- 
nal sclerites of each thoracic segment. (See sderite, and 
cuts under wesothorax and metathorax.) In ordinary de- 
scriptive entomology the name thorax has two special re- 
strictions : (1) to the pronotum of coleopterous, hemipte- 
rous, and orthopterous insects ; and (2) to the large me- 
aothorax of dipterous insects (see thoradform). 
3. In Crustacea and Aracltiiirta, a part of the 
body in advance of and in any way distin- 
guished from the abdomen or tail, but usually 
blended with the head to form a cephalothorax. 
In ordinary arachnidans, as spiders, and in the higher 
crustaceans, as crabs, lobsters, shrimps, prawns, and craw- 
fishes, several segments of the body are more or less 
completely fused in one mass; and the limbs are often 
so gradually metamorphosed into mouth-parts that even 
these indicia fail to discriminate a thorax from the head 
in every case. Generally, however, the bearing of eight 
or ten legs, developed as ambulatory organs, serves to de- 
note a thorax. In many or most of the lower or entomos- 
tracous crustaceans a thorax is indistinguishable from 
the abdomen as well as from the head, and the character 
of its appendages does not always decide the case. See 
Decapoda, Tetradecapoda, Thoracipoda, thoracetron. 
4. A breastplate, cuirass, or corselet; more 
especially, the cuirass or corselet worn by the 
ancient Greek warriors, corresponding to the 
lorica of the Bomans. It consisted of a breastplate 
and a backpiece fastened by buckles, and was often richly 
ornamented. Cornute, dimerous, Isthmlate thorax. 
See the adjectives. RectUS thoracis. See rectos. 
Transversus thoracis. Same as sternocostalis. 
thoret, adv. An obsolete form of there. 
Thoresdayt, A Middle English form of 
Thursday. 
Thoresenet, n. [ME., < Tliores, Thor's (see 
Thursday), + ene, even: see even 2 .'] The eve 
of Holy Thursday (Ascension day). 
Hii by gonne an holy Thoresene, then toun asaly ])ere 
Stalwardlyche 1 vaste ynou, noblemen is tht were. 
Rob. of Gloucester, p. 394 (quoted in Hampson, Medii JKvl 
(Kalendarium, II. 374). 
thoria (tho'ri-a), H. [NL.,< Thor.'] An oxid of 
thorium, Th0 2 . When pure it is a white powder, with- 
out taste, smell, or alkaline reaction on litmus. Its spe- 
cific gravity is 9.4. It is insoluble in all acids except sul- 
phuric. 
thoric (tho'rik), a. [< thorium + -i'c.] Of or 
pertaining to, or derived from, thorium. 
thorina (tho-ri'na), . [NL., < Thor + -inol.] 
Same as thoria. 
thorinum (tho-ri'num), n, [NL., < Thor + 
--.] Same as thorium. 
thorite (tho'rit), . [< Thor + -itet.~] A sili- 
cate of thorium, generally compact with con- 
choidal fracture, and of a black color, or, as in 
the variety orangite, orange-yellow, it is found 
in Norway in considerable quantity, especially in the 
neighborhood of Arendal. As found it always contains 
water, but the original mineral was doubtless anhydrous, 
and isomorphous with zirconium, silicate, or zircon. Some 
varieties of the mineral, called uranothorite, contain a con- 
siderable amount of uranium. 
thorium (tho'ri-um), n. [NL., < Thor + -ium.] 
Chemical symbol, Th; atomic weight, 231.9. 
The metallic base of the earth thoria, discover- 
ed by Berzelius, in 1828, in a mineral from Nor- 
way, to which the name of thorite is now given, 
and which consists essentially of the silicate of 
thorium. This earth has a)so been found in various other 
rare minerals. The metal thorium, as artificially prepared, 
resembles nickel in color, has a specific gravity of 7.66 to 
7.8, takes fire when heated in the air, and burns with a 
bright flame ; it dissolves readily in nitric acid, but only 
with difficulty in hydrochloric acid. Its chemical rela- 
tions place it in the same group with tin. Also thorinum. 
thorlt, *' An obsolete form of thirn. 
thorn 1 (thorn), n. [< ME. thorn, < AS. thorn = 
05. OFries. thorn = D. doom = MLG. dorn = 
OHG. MHG. G. dorn = Icel. thorn = Sw. torn 
= Dan. torn, tjorn = Goth, thaurnus, thorn, = 
OBulg. tr&nu = Serv. Bohem. trn = Pol. tarn, 
a thorn, = Russ. ternu, the blackthorn; cf. 
Skt. tarna, a blade of grass.] 1. A sharp ex- 
crescence on a plant: usually a branch, or the 
termination of a stem or branch, indurated, 
leafless, and attenuated to a point; a spine; 
a prickle. See spine, 1. 
O thin heaued wes set te crune of scharpe thornes, that 
with eauriche thorn wrang ut te reade blod of thin heali 
heaued. Wooing of Our Lord (Morris and Skeat, 1. 127). 
But ne're the rose without the thorn. 
Uerrick, The Rose. 
2. Figuratively, that which wounds or annoys; 
a cause of discomfort or irritation; a painful 
circumstance. 
I am amazed, methinks, and lose my way 
Anion^ the thftrnn and dangers of this world. 
Shak., K. John, iv. 3. 141. 
6300 
3. One of numerous thorny shrubs or trees, 
especially the members of the genus Creitayiix, 
otherwise called haw. These are low trees or shrubs 
with abundant white blossoms, and small apple-like fruit 
Flowering Branch of Washington Thorn (Cratafas tordala). 
a, the fmit ; b, leaf, showing the nervation. 
sometimes edible. The wood is hard and close-grained 
In some species, as the hawthorn, useful for turnery and 
even for wood-engraving. Several acacias and various 
other plants receive the name. See hatcthorn, and specific 
names below. 
The rose also mid hire rude [redness], 
That cumeth ut of the thorne wude. 
Owl and Nightingale, 1. 444 (Morris and Skeat, I. 183). 
All about the thorn will blow 
In tufts of rosy-tinted snow. 
Tennyson, Two Voices. 
4. In zool., some sharp process, horn, or spine. 
See spine, 3. 5. Inetow.,one of certain geom- 
etrid moths : an English book-name. The little 
thorn is Epione aduenaria; the early thorn is 
Selenia illunaria. 6. In lace-making, a small 
pointed projection used to decorate the cor- 
don-net, etc. Compare spine, 5. 7. The Anglo- 
Saxon letter b, equivalent to th; also, the cor- 
responding character in Icelandic. 
The English letter thorn, ]>, survived and continued in 
use down to the 15th century, when it was transformed 
to y. Kncyc. Brit., XVIII. 160. 
A thorn in the flesh or side, a source of constant an- 
noyance. 
There was given to me a thorn [or stake, E. V., margin] 
in thellesh, the messenger of Satan to buffet me, lest I 
should be exalted above measure. 2 Cor. xiL 7. 
Buffalo-thorn, Acacia Latronum, of India, a low tree 
with an umbrella-like top when old, and bearing long 
prickles. Christ's thorn. See Christ's-thorn, Paliurus, 
and nebbuk-tree. In Germany the holly is said to be the 
Christ's-thorn. Cockspur-thorn, the American Cratae- 
gus Cms-galli, also called Newcastle thorn. It reaches the 
height of 30 feet, is of a table-like growth, and has dark 
shining leaves, and thorns 4 inches long. It is planted for 
ornament in Europe, being perhaps the best American 
species for the purpose, as it is also for hedging. Egyp- 
tian thorn, Acacia Arabica {A. vera), one of the gum- 
arabic trees. Elephant-thorn, Acacia tomentom. 
Evergreen thorn, the pyracanth, Crateegus Pi/racantha, 
of southern Europe. It is a favorite in culture for its lux- 
uriant evergreen foliage and abundant orange-scarlet fruit. 
Being of a spreading and trailing habit, it is in England 
often trained upon walls. Glastonbury thorn, a variety 
of hawthorn, Crateegus Oxyacantha, var. preecox, which 
puts forth leaves and flowers about Christmas. This va- 
riety is said to have originated at Glastonbury Abbey, Eng- 
land, and it was believed that the original tree was the staff 
with which Joseph of Arimathea aided his steps on his 
wanderings from the Holy Land to Glastonbury, where, 
according to tradition, he became the founder of the cele- 
brated abbey. Jerusalem thorn. See Parkinsonia. 
Jews' thorn. Same as Christ's-thorn. Karoo thorn, 
the karoo doorn or doom boom of South Africa, Acacia 
horrida, a tree with very sharp spines from J inch to 3 
inches long. Lily thorn, a plant of the West Indian 
rubiaceous genus Catesbeea, particularly C. spinosa with 
large yellow nodding flowers, and C. pamflora with small 
white flowers. These plants are spiny in the axils of the 
leaves. Newcastle thorn. See cockspur-thorn, above. 
Parsley-leafed thorn, the parsley-haw, Crateeyui apii- 
folia, of the southern United States. Pear-thorn. Same 
as pear-haw (which see, under haw). Pyracanth thorn, 
the evergreen thorn. Sallow-thorn. See Hippophae. 
Scarlet-fruited thorn, the scarlet or red haw, Cratairus 
coccinea, a small tree common northward in North Amer- 
ica, with finely cut-toothed leaves and small scarlet, bare- 
ly edible haws. Scorpion-thorn, scorpion's thorn. 
Same as scorpion-plant, 2. September thorn. See Sep- 
tember. Silkworm -thorn, a small Chinese tree, Cud- 
rania triloba, of the nettle family. Its leaves are con- 
sidered as good as those of the mulberry for silkworms, 
but are more difficult to gather on account of thorns. 
Thirsty thorn, Acacia Seyal. Walt-a-hlt thorn, the 
grapple-plant. Washington thorn, Crateegus cordata, 
found in Virginia, and thence southward and westward. 
It was formerly widely planted for hedges, being dissem- 
inated from near Washington city. See cut above. Way- 
thorn, the buckthorn, Rhamnus catharticus: so called 
as springing up along highways. [Prov. Eng.] White 
thorn, (a) In England, the common hawthorn : so called 
from its lighter bark in contrast with the sloe or black- 
thorn, (b) In the United States, sometimes, the scarlet- 
fruited thorn, (c) See Jlacrocnemmn. Willow-thorn. 
Same as Kallow-thorn. (See also blackthorn, buckthfirn, catn- 
fl's-thfrrn, mouse-thorn, orange-thorn.) 
thorn-bird 
thorn 1 (thorn), r. t. [< tl/iirn^, .] 1. To prick 
or pierce with or as with a thorn. [Rare.] 
I am the only rose of all the stock 
That never thorn'd him. 
Tennyson, Harold, i. 1. 
2. To fasten with a thorn. 
Somtimes the Plane, somtimes the Vine they shear, 
Choosing their fairest tresses heer and there ; 
And with their sundry locks, thorn'd each to other, 
Their tender limbs they hide from Cynthias Brother. 
Sylvester, tr. of Uu Bartas's Weeks, ii., The Handy-Urafts. 
thorn' 2 t (thorn), a. [Origin obscure.] Sup- 
plied (?). 
Ye'll eat and drink, my merry men a', 
An' see ye be weell thorn. 
Sir Patrick Spens (Child's Ballads, III. 339). 
thorn-t, ' ' [< tltorn'l, a.] To be supplied (?). 
When they had eaten and well drunken, 
And a' had thorn'd fine ; 
The bride's father he took the cup, 
For to serve out the wine. 
Sweet waiie and Fair Maisry (Child's Ballads, II. 335). 
thorn-apple (thorn'ap"!), H. 1. A plant of the 
genus Datura, chiefly I). Stramonium, The name 
refers to the large spiny capsule. See stramo- 
nium. 2. A fruit of some species of Cratxi/un 
or thorn-tree ; a haw; 
also, the tree itself. 
thornback (thorn'- 
bak), n. [< ME. 
tliombak. thornbake ; 
< thorni .+ 6acA-l.] 
1. A kind of ray or 
skate, Kaia clavata, 
common on the Brit- 
ish coasts, distin- 
guished by the short 
and strong spines 
which are scattered 
over the back and 
tail. It grows about 2 
feet long, and is very vo- 
racious, feeding on small 
flounders, herrings, sand- 
eels, crabs, lobsters, etc. Thornback (Raifi clavata). 
Many are taken every year, 
and the flesh is considered to be excellent. The female is 
in Scotland called maiden-skate. 
The spreading ray, the thornback thin and flat. 
J. Dennys (Arber's Eng. Garner, I. 166). 
2. The common British spider-crab, Maia squi- 
nado. Sometimes called king-crab. See cut 
under Maia. 
thornback-ray (thorn ' bak - ra), n. Same as 
thornback, 1. 
thornbill (thorn'bil), n. A humming-bird of the 
genus Khampho- 
micron : a book- 
name. These not- 
able hummers are 
large (averaging 
over four inches 
long), with broad 
forked tail, the gor- 
get pendent like a 
beard, and special- 
ly short sharp bill 
(whence both the 
generic and vernac- 
ular names). Six 
species are de- 
scribed, one of the 
best-known being 
Ii. heteropogon. 
They range from 
the Colombian 
States through Ecuador, Peru, and Bolivia. The genus 
has three synonyms Chalcostigma, Lampropogon, and 
Eupotfonus. 
thorn-bird (thorn 'berd), H. A South Ameri- 
can dendrocolaptiue bird, originally Furnariit.* 
anitmbi (Vieillot, after Azara), now Anumbiux 
acuticaudatns (and rarely Spheno-pyaa anunibi). 
Thornbill {Rhamthomicron httcroposoifi. 
It is about 8 inches long, brown varied with black, white, 
and chestnut, and noted for the great size of the nest 
which it builds, of twigs and thorns, in bushes. It is a 
well-known Argentine type, a sort of large synallaxine 
liird \\itli short wings, stout feet, and sharp tail-fi'iithers. 
