metastoma 
, mouth.] In Crustacea, a median de- 
velopment, often bifid, of the ventral part of 
a somite immediately behind the mouth. It is 
the so-called labium or 'under lip, composed of small 
pieces immediately below or behind the mouth. Also 
called hypostoma. See the quotation, and cut under cepha- 
lothorax. 
On each side of, and behind, the mouth [of the crawfish] 
are two little elongated oval calcified plates, between 
which an oval process, setose at its extremity, proceeds 
downward and forward, and lies in close apposition with 
the posterior face of the mandible of its side. This is one- 
half of what is termed by most authors the labium ; but, 
to avoid confusion with the labium of Insecta, from which 
it is wholly different, it may be called the metastoma. 
Huxley, Anat. Invert., p. 272. 
metatarsal (met-a-tar'sal), a. and n. [< meta- 
tarsus + -a/.] I', a. Of or pertaining to the 
metatarsus, or to one of the bones that form it. 
II. n. One of the bones of the metatarsus. 
They are not more than five in number, reckoned as first, 
etc., from the inner to the outer side of the foot. When 
there are fewer than five, it is always the lateral metatar- 
sals which have disappeared, so that an animal with three 
metatarsals has lost the first and fifth ; in one with a single 
metatarsal the third or middle one remains. Metatarsals 
may ankylose together, as two do in the metatarsus of the 
ox, and three in that of any recent bird : in the latter case 
the compound bone is further complicated by fusion with 
it of tarsal elements, constitutinga tarsometatarsus (which 
see). See cut at metatarsu*. Accessory metatarsal, 
in ornith. See metatarsus, 1. 
metatarsale (met"a-tar-sa'le), n.; pi. metatar- 
salia (-li-a). [NL.: see metatarsal."] A bone 
of the metatarsus; one of the metatarsals. 
metatarsalgia (mefa-tar-sarji-a), n. [NL., 
< metatarsus + Gr. a/.yof, pain.] In pathol., 
pain in the metatarsus. Lancet, No. 3423, 
p. 707. 
metatarse (met'a-tars), n. [< NL. metatarsus, 
q. v.] The metatarsus. 
metatarsi, . Plural of metatarsus. 
met at ar so digital (met-a-tar-so-dij'i-tal), a. 
[< NL. metatarsus + L. digitus, finger, + -al.~\ 
Same as metatarsophalangeal. 
metatarsophalangeal (met-a-tar"so-fa-lan'je- 
al), a. [< NL. metatarsus + phalanges + -al.~\ 
Of or pertaining to the metatarsus and to the 
phalanges: as, a metatarsophalangeal articu- 
lation or ligament. 
metatarsus (met-a-t&r'sus), .; pi. metatarsi 
(-si). [NL., < 
Gr. fiera, be- 
yond, + rapaof, 
in mod. sense 
'tarsus': see 
tarsus.] 1. The 
middle seg- 
ment of the 
three of which 
the foot, or 
third division 
of the hind 
limb, consists, 
considered 
with special 
reference to its 
bony struc- 
ture. It is the 
part of the foot 
between the tar- 
sus and the toes, 
Front of Left Tarsus (Tarsometatarsus) of 
w^h dl th g e tart 5fS! " ft ~* to 'w*". -- 
and composed of a, articular facet for inner condyle of tibia; 
five bones. (See *, articular facet for outer condyle of tibia ; 
cut under foot I c < c - tw foramina, showinc incomplete fu- 
In a hnrp it in t hi- slon of thtee metatarsals ; ^pojm of attach- 
in a norse It 18 tne ment of accessory metatarsal ; 2. 3, 4. articu- 
part Of the hind lar facets for second, third, and fourth toes. 
leg between the 
hock and the fetlock, and has but one functional bone. 
In birds it is the part popularly called the shank, and in 
descriptive ornithology known as the tarsus. In most 
birds the metatarsus is naked and scaly, and extends from 
the bases of the toes to the suffrage or first joint above. 
It usually consists of a single stout bone, representing 
three metatarsals fused together, and further complicated 
by the fusion of distal tarsal elements with its proximal 
end. In birds with four toes the metatarsus includes a 
small separate bone known as the accessory metatarsal, 
which is the metatarsal bone of the hallux or hind toe, 
the metatarsus hallucis. 
2. In en torn. : (a) The first one of the joints of 
the tarsus, when it is large or otherwise dis- 
tinguished from the rest, which are then called 
collectively the dacti/his. Also called planta, in 
which case the other joints are collectively known as the 
digitus. The peculiarly expanded and bristly metatarsus 
or planta of bees is known as the scapula, (ft) With 
some authors, the hind foot; the entire tarsus 
of each hind leg ; each of the third pair of tarsi. 
When this nomenclature is used, the tarsus of the middle 
leg is called metatarsus and that of the fore leg protarsus. 
(c) The sixth joint of a spider's leg, being the 
first of the two which form the foot Flexor 
metatarsi. Same as peroneus tertius (which see, under 
perotwm). 
, put 
see 
3736 
metatartaric (met * a -tar- tar Mk), a. [< Gr. 
fitrd, with, + E. tartaric.~\ A word used only 
in the following phrase : Metatartaric add, an 
amorphous form of ordinary tartaric acid, prepared by 
keeping it for some time at its melting temperature. 
metatatic (met-a-tat'ik), a. [< Gr. fierd, with, 
+ rdaif ("ran-), tension, intensity, force, < rarof, 
verbal adj. of reivuv, stretch: see tend."] Re- 
lating to a coincidence of directions of stress 
and strain Metatatic isotrophy, plane, etc. See 
the nouns. Orthogonal or principal metatatic axes. 
See axisl. 
metatatically (met-a-tat'i-kal-i), adv. In a 
metatatic manner or sense. 
metatela (met-a-te'la), n. ; pi. metatelce (-le). 
[NL., < Gr. fiera, beh'ind, + NL. tela, q. v.] 
The tela of the metencephalon ; the inferior cho- 
roid tela; in man, a very delicate tissue of the 
brain, more commonly called velum medullare 
posterius. See tela, velum. Wilder and Gage. 
Metatheria (met-a-the'ri-&), . pi. [NL., < 
Gr. fitTa, between, + fh/piov, a wild beast.] A 
subclass of Mammalia including the existing 
Marsupialia and their hypothetical extinct an- 
cestors, as well as other mammals intermediate 
between marsupials and placental mammals. 
The marsupials are the only known examples, the term 
being thus equivalent to Didelphia. It is correlated with 
Prototheria and Eutheria. 
metatherian (met-a-the'ri-an),a. and n. I. a. 
Pertaining to the Metatheria, or having their 
characters: as, a metatherian mammal; the 
metatherian type. 
II. n. A member of the Metatheria. 
metathesis (me-tath'e-sis), n. [LL., < Gr. 
feovf, transposition, metathesis, < peTariBcvai 
over, transpose, < [terd, over, + nKvai, put 
thesis.] 1. In gram., transposition, more es- 
pecially of the letters, sounds, or syllables of a 
word, as in the ease of Anglo-Saxon dcsian, ds- 
cian, English ax, ask; Anglo-Saxon brid, Eng- 
lish bird. 
The transposition of vowels and liquids metathesis 
is an ordinary and familiar phenomenon of language. 
J. Hadley, Essays, p. 159. 
2. In surg., a change in place of a morbid sub- 
stance ; an operation removing a morbific agent 
from one part to another, as in couching for 
cataract. 3. In logic, same as conversion. 
metathetic (met -a- thet'ik), a. [(metathesis 
(-thet-) + -ic.~] Of the nature of or containing 
metathesis. 
metathetical (met-a-thet'i-kal), a. [< meta- 
thetic + -a?.] Same as metathetic. 
metathoracic (met"a-tho-ras'ik), a. [< meta- 
thorax + -jc.] Of or pertaining to the meta- 
thorax of an insect Metathoracic case, the meta- 
thoracotheca. Metathoracic legs, the third pair of 
legs of any hexapod; the hind legs. Metathoracic 
wings, the posterior or lower wings. 
metathoracotheca (met-a-thd"ra-ko-the'ka), 
n.; pi. metathoracotheca! (-se). [NL., < meta- 
thorax + 6>/Kti, a case.] 
In entom., the meta- SL .g 
thoracic case, or that /Q O\ 
part of the integu- / \ 
ment of a pupa coyer- / c \ 
ing tha metathorax. K^ ^- L - 
It is generally indis- 
tinguishable in the 
Lepidoptera and Dip- 
tera. 
metathorax (met-a- 
tho'raks), n. [NL., < 
Gr. [icrd, beyond, + 
Otipaj, the chest.] In 
entom., the third and 
last segment of the 
thorax, succeeding the 
mesothorax, preceding the abdomen, and bear- 
ing the third pair of legs and the second pair 
of wings Declivity of the metathorax. See de- 
clivity. 
metatome (met'a-tom), . [< Gr. perd, among, 
between, + TOUJI, a cutting, < Ttfivuv, Tafielv, cut.] 
In arch . , the space between two dentils. Gwilt. 
metaxin (me-tak'sin), . [< Gr. //eraf r, between 
(< uerd, between), + -in 2 .] A distinct proteid 
substance entering into the composition of the 
fibrillar structure of chloroplastids. 
metaxite (me-tak'slt), . [< Gr. /terajl; be- 
tween, + -jte 2 .] In mineral., a variety of ser- 
pentine occurring in fibrous or columnar forms 
with a silky luster. 
metayage (me-ta'yaj; F. pron. ma-ta-yazh'), n. 
[< F. metayage; as mctay(er) + -age."] The cul- 
tivation of land on shares ; the metayer system 
of agriculture. 
Metayage that is to say, a kind of temporary partner- 
ship or joint venture, in which the proprietor supplies the 
Metathorax, shaded, between 
mesothorax (a) and abdomen (/) ; 
c, prothorax ; d, head. 
mete 
land and the seed, and the peasants do all the work with 
their own horses and implements. 
D. M. Wallace, Russia, p. 519. 
metayer (me-ta'yer; F. pron. ma-tii-ya'), [< 
V. metayer, < ML. medietarius, one who tills 
land for half the produce, < L. medieta(t-)s, mid- 
dle place, half: see mmety, mediety.~] A culti- 
vator who tills a farm or piece of ground for 
the owner, on condition of receiving a share of 
the produce, generally a half, the owner gener- 
ally furnishing the whole or a part of the stock, 
tools, etc. This system of cultivation, called metayage 
or the metayer system, prevails in the central and southern 
parts of France and in most of Italy, and is practised to a 
considerable extent in the southern United States. 
The principle of the metayer system is that the labourer 
or peasant makes his engagement directly with the land- 
owner, and pays, not a fixed rent, either in money or in 
kind, but a certain proportion of the produce, or rather of 
what remains of the produce after deducting what is con- 
sidered necessary to keep up the stock. The proportion is 
usually, as the name imports, one-half ; but in several dis- 
tricts in Italy it is two-thirds. Respecting the supply of 
stock, the custom varies from place to place ; in some places 
the landlord furnishes the whole, in others half, in others 
some particular part, as for instance the cattle and seed, 
the labourer providing the implements. 
J. S. Mitt, Pol. Econ., II. viif. :. 
The metayer has less motive to exertion than the peasant 
proprietor, since only half the fruits of his industry, in- 
stead of the whole, are his own. 
J. S. Mm, Pol. Econ., II. viii. 2. 
metaynt, A Middle English form of mitten. 
Metazoa (met-a-zo'a), n. pi. [NL., pi. of meta- 
zoon, q. v.] All those animals which are above 
the Protozoa, and which in the course of their 
development undergo certain metamorphoses, 
consisting of the primary segmentation of a 
true egg or ovum, and the subsequent passage 
through an embryonic condition in which they 
possess at least two distinct germinal layers ; 
animals exhibiting cellular differentiation. The 
Metazoa are distinguished from the Protozoa in that the 
substance of the body is differentiated into histogenic ele- 
mentsthat is to say, into cells. In all the Metazoa the 
ovum has the form of a nucleated cell, the first step in 
the process of development being the production of a 
blastoderm by the subdivision of that cell, the cells of the 
blastoderm giving rise in turn to two layers of cells, endo- 
derm and ectoderm, between which, in most cases, a 
mesoderm appears, to be itself split in two layers ; such a 
four-layered germ developing finally all the histological 
elements of the adult body. With the exception of certain 
parasites, and the extremely modified males of af ewspecies, 
all these animals possess a permanent alimentary cavity 
lined by a special layer of endodermal cells. Sexual re- 
production is the rule, and very generally the male ele- 
ment has the form of filiform spermatozoa. The lowest 
term in the series of the Metazoa is represented by the Pori- 
.fera or sponges. Those of the Metazoa which possess a 
notochord, and in the adult state have the trunk divided 
into segments or myotomes, constitute the subkingdom 
Vertebrata; the rest are the several suhkingdomsof inver- 
tebrates. Compare Protozoa. See Mesozoa, and cuts under 
ifastrulation. 
metazoan (met-a-zd'an), a. and n. [< Metasoa 
+ -an."] I. a. Of or pertaining to the Metazoa. 
The Metazoan segmentation of the ovum. 
Encyc. Brit., XX. 419. 
II. n. A member of the Metazoa; a meta- 
zoOn. 
metazoic (met-a-zo'ik), a. [< Metazoa + -/<'.] 
Pertaining to the Metazoa, or having their char- 
acters. 
metazodn (met-a-zo'on), . [NL., < Gr. /JETO, 
after, + f Qov, an animal.] One of the Metazoa ; 
any animal which has a gastrula stage, or which 
undergoes in the course of its development 
a process of delamination or of gastrulation, 
whether by emboly or by epiboly. 
If we employ the term gastrula in the broad sense, . . . 
it may be truly said that every metazoon passes through 
the gastrula stage in the course of its development. 
Huxley, Anat. Invert., p. 584. 
mete 1 (met), r. ; pret. and pp. meted, ppr. meting. 
[< ME. meten, < AS. metan (pret. matt, pi. nice- 
ton, pp. meten), measure, = OS. metan = OFries. 
meta = D. meten = MLG. LG. meten = OHG. 
mezan, mezzan, MHG. mezzeti, G. mexsen, mea- 
sure, = Icel. meta, value, = Sw. mala = Dan. 
dial. ma:de, measure, = Goth, mitan, measure; 
cf. the secondary verb, OHG. mezon, mezzoii. 
regulate. = Goth, miton, consider; Teut. ^ met 
= L. and Gr. -\/ med, in L. modus, measure (> E. 
mode 1 , moderate, modest, etc.), modius, a certain 
measure, Gr. fiiitftvof, a certain measure, ueit- 
aSai, consider, etc. The L. metiri (T/ met), mea- 
sure (whence ult. E. measure, mensurate, etc.), 
is not exactly cognate with AS. metan, but ap- 
pears to be from the same ult. root, namely 
I/ ma (Skt. -\/ nid), measure, whence also ult. E. 
mrtei'V, meter 3 , metric^, metric'*, etc.] I. tnnix. 
1. To ascertain the quantity, dimensions, ex- 
tent, or capacity of, by comparison with a stan- 
dard; measure. 
