Chapter 46

Is"chi*al (s"k*al), a. (Anat.) Of or pertaining to the ischium or hip; ischiac; ischiadic; ischiatic.

Ischial callosity (Zoöl.), one of the patches of thickened, hairless, and often bright-colored skin, on the buttocks of many apes, as the drill.

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Is`chi*at"ic (s`k*d"k), a. (Anat.) Same as Ischial.

Is`chi*o*cap"su*lar (?; 135) a. [Ischium + capsular.] (Anat.) Of or pertaining to the ischium and the capsule of the hip joint; as, the ischiocapsular ligament.

Is`chi*o*ce"rite (?), n. [Gr. 'ischi`on the hip + ke`ras a horn.] (Zoöl.) The third joint or the antennæ of the Crustacea.

{ ||Is"chi*on (?), ||Is"chi*um (?), } n. [L., Gr. 'ischi`on.] 1. (Anat.) The ventral and posterior of the three principal bones composing either half of the pelvis; seat bone; the huckle bone.

2. (Zoöl.) One of the pleuræ of insects.

Is`chi*op"o*dite (?), n. [Gr. 'ischi`on the hip joint + &?;, &?;, foot.] (Zoöl.) The third joint of the typical appendages of Crustacea.

Is`chi*o*rec"tal (?), a. [Ischium + rectal.] (Anat.) Of or pertaining to the region between the rectum and ishial tuberosity.

Is`chu*ret"ic (?), a. Having the quality of relieving ischury. -- n. An ischuretic medicine.

Is"chu*ry (?), n. [L. ischuria, Gr. &?;; &?; to hold, check + &?; urine: cf. F. ischurie.] (Med.) A retention or suppression of urine.

-ise (?). See -ize.

I`sen*trop"ic (?), a. [Is- + entropy + -ic.] (Physics) Having equal entropy.

Isentropic lines, lines which pass through points having equal entropy.

I*seth`i*on"ic (?), a. [Is- + ethionic.] (Chem.) Pertaining to, derived from, or designating, an acid, HO.C2H4.SO3H, obtained as an oily or crystalline substance, by the action of sulphur trioxide on alcohol or ether. It is derivative of sulphuric acid.

-ish (?). [AS. -isc; akin to G. -isch, OHG. -isc, Goth. & Dan. -isk, Gr. &?;. Cf. -esque.] A suffix used to from adjectives from nouns and from adjectives. It denotes relation, resemblance, similarity, and sometimes has a diminutive force; as, selfish, boyish, brutish; whitish, somewhat white.

-ish. [OE. -issen, fr. F. -is, -iss- (found in the present particle, etc., of certain verbs, as finir to finish, fleurir to flourish), corresponding to L. -escere, an inchoative ending.] A verb ending, originally appearing in certain verbs of French origin; as, abolish, cherish, finish, furnish, garnish, impoverish.

Ish"ma*el*ite (?), n. 1. A descendant of Ishmael (the son of Abraham and Hagar), of whom it was said, "His hand will be against every man, and every man's hand against him." Gen. xvi. 12.

2. One at enmity with society; a wanderer; a vagabond; an outcast. Thackeray.

3. See Ismaelian.

Ish"ma*el*i`tish (?), a. Of, pertaining to, or resembling, an Ishmaelite or the Ishmaelites.

I"si*ac (?), a. [L. Isiacus, Gr. &?;, fr. &?;.] Pertaining to the goddess Isis; as, Isiac mysteries.

I"si*cle (?), n. A icicle. [Obs.]

Is`i*do"ri*an (?), a. Pertaining, or ascribed, to Isidore; as, the Isidorian decretals, a spurious collection of decretals published in the ninth century.

I"sin*glass (?), n. [Prob. corrupted fr. D. huizenblas (akin to G. hausenblase), lit., bladder of the huso, or large sturgeon; huizen sturgeon + blas bladder. Cf. Bladder, Blast a gust of wind.]

1. A semitransparent, whitish, and very pure form of gelatin, chiefly prepared from the sounds or air bladders of various species of sturgeons (as the Acipenser huso) found in the rivers of Western Russia. It used for making jellies, as a clarifier, etc. Cheaper forms of gelatin are not unfrequently so called. Called also fish glue.

2. (Min.) A popular name for mica, especially when in thin sheets.

I"sis (?), n. [L., the goddess Isis, fr. Gr. &?;.]

1. (Myth.) The principal goddess worshiped by the Egyptians. She was regarded as the mother of Horus, and the sister and wife of Osiris. The Egyptians adored her as the goddess of fecundity, and as the great benefactress of their country, who instructed their ancestors in the art of agriculture.

2. (Zoöl.) Any coral of the genus Isis, or family Isidæ, composed of joints of white, stony coral, alternating with flexible, horny joints. See Gorgoniacea.

3. (Astron.) One of the asteroids.

Is"lam (?), n. [Ar. islm obedience to the will of God, submission, humbling one's self, resigning one's self to the divine disposal. Cf. Moslem.]

1. The religion of the Mohammedans; Mohammedanism; Islamism. Their formula of faith is: There is no God but Allah, and Mohammed is his prophet.

2. The whole body of Mohammedans, or the countries which they occupy.

Is"lam*ism (?), n. [Cf. F. islamisme.] The faith, doctrines, or religious system of the Mohammedans; Mohammedanism; Islam.

Is"lam*ite (?), n. A Mohammedan.

Is`lam*it"ic (?), a. Of or pertaining to Islam; Mohammedan.

Is"lam*ize (?), v. i. & t. [imp. & p. p. Islamized (?); p. pr. & vb. n. Islamizing (?).] To conform, or cause to conform, to the religion of Islam.

Is"land (?), n. [OE. iland, yland, AS. gland, &?;gland, &?;glond; g, &?;g, island + land, lond, land. AS. g, &?;g, is akin to AS. eá water, river, OHG. &?;uwa, G. au meadow, Icel. ey island, Dan. & Sw. ö, Goth. ahwa a stream, water, L. aqua water. The s is due to confusion with isle. Cf. Ait, Eyot, Ewer, Aquatic.]

1. A tract of land surrounded by water, and smaller than a continent. Cf. Continent.

2. Anything regarded as resembling an island; as, an island of ice.

3. (Zoöl.) See Isle, n., 2.

Islands of the blessed (Myth.), islands supposed to lie in the Western Ocean, where the favorites of the gods are conveyed at death, and dwell in everlasting joy.

Is"land (?), v. t. 1. To cause to become or to resemble an island; to make an island or islands of; to isle. Shelley.

2. To furnish with an island or with islands; as, to island the deep. Southey.

Is"land*er (?), n. An inhabitant of an island.

Is"land*y (?), a. Of or pertaining to islands; full of islands. Cotgrave.

Isle (?), n. [Obs.] See Aisle.

Isle (?), n. [OF. isle, F. île, L. insula; cf. Lith. sala. Cf. Insulate.]

1. An island. [Poetic]

Imperial rule of all the seagirt isles.

Milton.

2. (Zoöl.) A spot within another of a different color, as upon the wings of some insects.

Isle, v. t. To cause to become an island, or like an island; to surround or encompass; to island. [Poetic]

Isled in sudden seas of light.

Tennyson.

Is"let (?), n. [OF. islette (cf. F. îlot), dim. of isle.] A little island.

-ism (?). [F. -isme, or L. -ismus, Gr. &?;.] A suffix indicating an act, a process, the result of an act or a process, a state; also, a characteristic (as a theory, doctrine, idiom, etc.); as, baptism, galvanism, organism, hypnotism, socialism, sensualism, Anglicism.

Ism, n. [See ism, above.] A doctrine or theory; especially, a wild or visionary theory. E. Everett.

The world grew light-headed, and forth came a spawn of isms which no man can number.

S. G. Goodrich.

{ Is`ma*e"li*an (?), Is"ma*el*ite (?), } n. (Eccl.) One of a sect of Mohammedans who favored the pretensions of the family of Mohammed ben Ismael, of the house of Ali.

{ I"so- (?), Is- (?). } [Gr. 'i`sos equal.] A prefix or combining form, indicating identity, or equality; the same numerical value; as in isopod, isomorphous, isochromatic. Specif.: (a) (Chem.) Applied to certain compounds having the same composition but different properties; as in isocyanic. (b) (Organic Chem.) Applied to compounds of certain isomeric series in whose structure one carbon atom, at least, is connected with three other carbon atoms; -- contrasted with neo- and normal; as in isoparaffine; isopentane.

I"so*bar (?), n. [Iso- + Gr. &?; weight.] (Phys. Geog.) A line connecting or marking places upon the surface of the earth where height of the barometer reduced to sea level is the same either at a given time, or for a certain period (mean height), as for a year; an isopiestic line. [Written also isobare.]

I`so*bar"ic (?), a. (Phys. Geog.) Denoting equal pressure; as, an isobaric line; specifically, of or pertaining to isobars.

I"so*bar*ism (?), n. The quality or state of being equal in weight, especially in atmospheric pressure. Also, the theory, method, or application of isobaric science.

I`so*bar`o*met"ric (?), a. [Iso + barometric.] (Phys. Geog.) Indicating equal barometric pressure.

I`so*bath"y*therm (?), n. [Iso- + Gr. &?; deep + &?; heat.] (Phys. Geog.) A line connecting the points on the surface of the earth where a certain temperature is found at the same depth.

I`so*bath"y*ther"mic (?), a. Of or pertaining to an isobathytherm; possessing or indicating the same temperature at the same depth.

I`so*ceph"a*lism (?), n. [From Gr. &?; like-headed. See Iso-, and Cephalon.] (Art) A peculiarity in the design of bas-relief by which the heads of human figures are kept at the same height from the ground, whether the personages are seated, standing, or mounted on horseback; -- called also isokephaleia.

I"so*chasm (?), n. [Iso- + chasm.] (Phys. Geog.) A line connecting places on the earth's surface at which there is the same mean frequency of auroras.

I`so*chas"mic (?), a. Indicating equal auroral display; as, an isochasmic line.

I"so*cheim ("s*km), n. [Iso- + Gr. &?;, &?;, winter.] (Phys. Geog.) A line connecting places on the earth having the same mean winter temperature. Cf. Isothere.

{ I`so*chei"mal, I`so*chi"mal } (?), a. Pertaining to, having the nature of, or making, isocheims; as, an isocheimal line; an isocheimal chart.

{ I`so*chei"me*nal (?), I`so*chi"me*nal } a. The same as Isocheimal.

I`so*chei"mic (?), a. The same as Isocheimal.

I`so*chi"mene (?), n. The same as Isocheim.

I`so*chro*mat"ic (?), a. [Iso- + chromatic.] (Opt.) Having the same color; connecting parts having the same color, as lines drawn through certain points in experiments on the chromatic effects of polarized light in crystals.

I*soch"ro*nal (?), a. [See Isochronous.] Uniform in time; of equal time; performed in equal times; recurring at regular intervals; as, isochronal vibrations or oscillations.

I`so*chron"ic (?), a. Isochronal.

I*soch"ro*nism (?), n. The state or quality of being isochronous.

I*soch"ro*non (?), n. [NL. See Isochronous.] A clock that is designed to keep very accurate time.

I*soch"ro*nous (?), a. [Gr. &?;; &?; equal + &?; time.] Same as Isochronal.

I*soch"ro*ous (?), a. [Iso- + Gr. &?; color.] Having the same tint or color throughout; uniformly or evenly colored.

{ I`so*cli"nal (?), I`so*clin"ic (?), } a. [Iso- + Gr. &?; to incline.] Of or pertaining to, or indicating, equality of inclination or dip; having equal inclination or dip.

Isoclinal lines (Magnetism), lines on the earth's surface connecting places at which a dipping needle indicates the same inclination or dip.

I`so*cry"mal (?), a. (Phys. Geog.) Pertaining to, having the nature of, or illustrating, an isocryme; as, an isocrymal line; an isocrymal chart.

I"so*cryme (?), n. [Iso- + Gr. &?; cold.] (Phys. Geog.) A line connecting points on the earth's surface having the same mean temperature in the coldest month of the year.

I`so*crym"ic (?), a. Isocrymal.

I`so*cy*an"ic (?), a. [Iso- + cyanic.] (Chem.) Designating an acid isomeric with cyanic acid.

Isocyanic acid, an acid metameric with cyanic acid, and resembling it in its salts. It is obtained as a colorless, mobile, unstable liquid by the heating cyanuric acid. Called technically carbimide.

I`so*cy`a*nu"ric (?), a. [Iso- + cyanuric.] (Chem.) Designating, or pertaining to, an acid isomeric with cyanuric acid, and called also fulminuric acid. See under Fulminuric.

I`so*di`a*bat"ic (?), a. [Iso- + Gr. &?; to pass through.] (Physics) Pertaining to the reception or the giving out of equal quantities of heat by a substance. Rankine.

Isodiabatic lines or curves, a pair of lines or curves exhibiting, on a diagram of energy, the law of variation of the pressure and density of a fluid, the one during the lowering, and the other during the raising, of its temperature, when the quantity of heat given out by the fluid during any given stage of the one process is equal to the quantity received during the corresponding stage of the other. Such lines are said to be isodiabatic with respect to each other. Compare Adiabatic.

I`so*di`a*met"ric (?), a. [Iso- + diametric.]

1. (Crystallog.) Developed alike in the directions of the several lateral axes; -- said of crystals of both the tetragonal and hexagonal systems.

2. (Bot.) Having the several diameters nearly equal; -- said of the cells of ordinary parenchyma.

I`so*di*mor"phic (?), a. [Iso- + dimorphic.] Isodimorphous.

I`so*di*mor"phism (?), n. Isomorphism between the two forms severally of two dimorphous substances.

I`so*di*mor"phous (?), a. [Iso- + dimorphous.] Having the quality of isodimorphism.

I`so*dul"cite (?), n. [Iso- + dulcite.] (Chem.) A white, crystalline, sugarlike substance, obtained by the decomposition of certain glucosides, and intermediate in nature between the hexacid alcohols (dulcite, mannite, etc.) and the glucoses.

I`so*dy*nam"ic (?), a. [Iso- + dynamic.] Of, pertaining to, having, or denoting, equality of force.

Isodynamic foods (Physiol.), those foods that produce a similar amount of heat. -- Isodynamic lines (Magnetism), lines on the earth's surface connecting places at which the magnetic intensity is the same.

I`so*dy"na*mous (?), a. [Gr. &?;. See Isodynamic.] Of equal force or size.

I`so*ge"o*therm (?), n. [Iso- + Gr. gh^ the earth + qe`rmh heat.] (Phys. Geog.) A line or curved surface passing beneath the earth's surface through points having the same mean temperature.

{ I`so*ge`o*ther"mal (?), I`so*ge`o*ther"mic (?), } a. Pertaining to, having the nature of, or marking, isogeotherms; as, an isogeothermal line or surface; as isogeothermal chart. -- n. An isogeotherm.

I`so*gon"ic (?), a. [Iso- + Gr. gwni`a angle.] Pertaining to, or noting, equal angles.

Isogonic lines (Magnetism), lines traced on the surface of the globe, or upon a chart, connecting places at which the deviation of the magnetic needle from the meridian or true north is the same.

I`so*gon"ic, a. (Zoöl.) Characterized by isogonism.

I*sog"o*nism (?), n. [Iso- + Gr. &?; offspring, generative parts.] (Zoöl.) The quality of having similar sexual zooids or gonophores and dissimilar hydrants; -- said of certain hydroids.

I`so*graph"ic (?), a. Of or pertaining to isography.

I*sog"ra*phy (?), n. [Iso- + -graphy.] Imitation of another's handwriting.

I`so*hy"e*tose` (?), a. [Iso- + Gr. "yeto`s rain.] (Phys. Geog.) Of or pertaining to lines connecting places on the earth's surface which have a mean annual rainfall. -- n. An isohyetose line.

I"so*la*ble (?), a. [See Isolate.] (Chem.) Capable of being isolated, or of being obtained in a pure state; as, gold is isolable.

I"so*late (?; 277), v. t. [imp. & p. p. Isolated (?); p. pr. & vb. n. Isolating (?).] [It. isolato, p. p. of isolare to isolate, fr. isola island, L. insula. See 2d Isle, and cf. Insulate.]

1. To place in a detached situation; to place by itself or alone; to insulate; to separate from others.

Short isolated sentences were the mode in which ancient wisdom delighted to convey its precepts.

Bp. Warburton.

2. (Elec.) To insulate. See Insulate.

3. (Chem.) To separate from all foreign substances; to make pure; to obtain in a free state.

I"so*la`ted (?), a. Placed or standing alone; detached; separated from others.

Isolated point of a curve. (Geom.) See Acnode.

I"so*la`ted*ly (?), adv. In an isolated manner.

I`so*la"tion (-l"shn), n. [Cf. F. isolation.] The act of isolating, or the state of being isolated; insulation; separation; loneliness. Milman.

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I"so*la`tor ("s*l`tr or s"*l`tr), n. One who, or that which, isolates.

I*sol"o*gous (?), a. [Iso- + Gr. lo`gos proportion.] (Chem.) Having similar proportions, similar relations, or similar differences of composition; -- said specifically of groups or series which differ by a constant difference; as, ethane, ethylene, and acetylene, or their analogous compounds, form an isologous series.

I"so*mer ("s*mr), n. [See Isomeric.] (Chem.) A body or compound which is isomeric with another body or compound; a member of an isomeric series.

I`so*mer"ic (-mr"k), a. [Iso- + Gr. me`ros part: cf. F. isomérique.] (Chem.) Having the same percentage composition; -- said of two or more different substances which contain the same ingredients in the same proportions by weight, often used with with. Specif.: (a) Polymeric; i. e., having the same elements united in the same proportion by weight, but with different molecular weights; as, acetylene and benzine are isomeric (polymeric) with each other in this sense. See Polymeric. (b) Metameric; i. e., having the same elements united in the same proportions by weight, and with the same molecular weight, but with a different structure or arrangement of the ultimate parts; as, ethyl alcohol and methyl ether are isomeric (metameric) with each other in this sense. See Metameric.

I*som"er*ide (?), n. (Chem.) An isomer. [R.]

I*som"er*ism (?), n. (Chem.) The state, quality, or relation, of two or more isomeric substances.

Physical isomerism (Chem.), the condition or relation of certain (metameric) substances, which, while chemically identical (in that they have the same composition, the same molecular weights, and the same ultimate constitution), are yet physically different, as in their action on polarized light, as dextro- and lævo-tartaric acids. In such compounds there is usually at least one unsymmetrical carbon atom. See Unsymmetrical.

I`so*mer`o*mor"phism (?), n. [Isomer + Gr. &?; form + -ism.] (Crystallog.) Isomorphism between substances that are isomeric.

{ I`so*met"ric (?), I`so*met"ric*al (?), } a. [Iso- + Gr. me`tron measure.] 1. Pertaining to, or characterized by, equality of measure.

2. (Crystallog.) Noting, or conforming to, that system of crystallization in which the three axes are of equal length and at right angles to each other; monometric; regular; cubic. Cf. Crystallization.

Isometric lines (Thermodynamics), lines representing in a diagram the relations of pressure and temperature in a gas, when the volume remains constant. -- Isometrical perspective. See under Perspective. -- Isometrical projection, a species of orthographic projection, in which but a single plane of projection is used. It is so named from the fact that the projections of three equal lines, parallel respectively to three rectangular axes, are equal to one another. This kind of projection is principally used in delineating buildings or machinery, in which the principal lines are parallel to three rectangular axes, and the principal planes are parallel to three rectangular planes passing through the three axes.

I"so*morph (?), n. [See Isomorphous.] A substance which is similar to another in crystalline form and composition.

I`so*mor"phic (?), a. Isomorphous.

I`so*mor"phism (?), n. [Cf. F. isomorphisme.] (Crystallog.) A similarity of crystalline form between substances of similar composition, as between the sulphates of barium (BaSO4) and strontium (SrSO4). It is sometimes extended to include similarity of form between substances of unlike composition, which is more properly called homœomorphism.

I`so*mor"phous (?), a. [Iso- + -morphous.] Having the quality of isomorphism.

||I`so*nan"dra (?), n. [Iso- + Gr. &?;, &?;, a man, male.] (Bot.) A ||genus of sapotaceous trees of India. Isonandra Gutta is the principal ||source of gutta-percha. || I`so*ne*phel"ic (?), a. [Iso- + Gr. &?; a cloud.] (Phys. Geog.) Having, or indicating, an equal amount of cloudiness for a given period; as, isonephelic regions; an isonephelic line.

I`so*nic"o*tine (?), n. [Iso- + nicotine.] (Chem.) A crystalline, nitrogenous base, C10H14N2, isomeric with nicotine.

I`so*nic`o*tin"ic (?), a. (Chem.) (a) Pertaining to, or derived from, isonicotine. (b) Pertaining to, or designating, an acid isomeric with nicotinic acid.

I`so*ni*tro"so- (?). [Iso- + nitroso-.] (Chem.) A combining form (also used adjectively), signifying: Pertaining to, or designating, the characteristic, nitrogenous radical, NOH, called the isonitroso group.

I`so*nom"ic (?), a. [Gr. &?;; &?; equal + no`mos law.] The same, or equal, in law or right; one in kind or origin; analogous; similar. Dana.

I*son"o*my (?), n. [Gr. &?;: cf. F. isonomie. See Isonomic.] Equal law or right; equal distribution of rights and privileges; similarity.

I*sop"a*thy (?), n. [Iso- + Gr. &?; suffering.] (Med.) (a) The system which undertakes to cure a disease by means of the virus of the same disease. (b) The theory of curing a diseased organ by eating the analogous organ of a healthy animal. Mayne. (c) The doctrine that the power of therapeutics is equal to that of the causes of disease.

I`so*pep"sin (?), n. [Iso- + pepsin.] (Physiol. Chem.) Pepsin modified by exposure to a temperature of from 40° to 60° C.

I`so*per`i*met"ric*al (?), a. [Gr. &?;; &?; equal + &?; circumference: cf. F. isopérimètre. See Perimeter.] (Geom.) Having equal perimeters of circumferences; as, isoperimetrical figures or bodies.

I`so*per*im"e*try (?), n. (Geom.) The science of figures having equal perimeters or boundaries.

I`so*pi*es"tic (?), a. [Iso- + Gr. &?; to press.] (Thermodynamics) Having equal pressure.

Isopiestic lines, lines showing, in a diagram, the relations of temperature and volume, when the elastic force is constant; -- called also isobars.

||I`so*pleu"ra (?), n. pl. [NL. See Iso-, and Pleura.] (Zoöl.) A ||subclass of Gastropoda, in which the body is symmetrical, the right ||and left sides being equal. || The intestine terminates at the posterior end of the body, and the gills and circulatory and reproductive organs are paired. It includes the chitons (Polyplacophora), together with Neomenia and Chætoderma, which are wormlike forms without a shell.

I"so*pod (?), a. (Zoöl.) Having the legs similar in structure; belonging to the Isopoda. -- n. One of the Isopoda.

||I*sop"o*da (?), n. pl. [NL. See Iso-, and -poda.] (Zoöl.) An order of ||sessile-eyed Crustacea, usually having seven pairs of legs, which are ||all similar in structure. || The body is usually depressed, with the abdominal segments short, and often consolidated in part. The branchiæ are on the abdominal appendages. The group includes the terrestrial pill bugs and sow bugs, with numerous marine forms. See Arthrostrata, Gribble.

I`so*pod"i*form (?), a. [Isopod + -form.] (Zoöl.) Having the shape of an isopod; -- said of the larvæ of certain insects.

I*sop"o*dous (?), a. Same as Isopod.

I`so*pog"o*nous (?), a. [Iso- + Gr. &?; beard.] (Zoöl.) Having the two webs equal in breadth; -- said of feathers.

I"so*prene (?), n. [Etymol. uncertain.] (Chem.) An oily, volatile hydrocarbon, obtained by the distillation of caoutchouc or gutta-percha.

I`so*pyc"nic (?), a. [Iso- + Gr. pykno`s dense.] (Physics) Having equal density, as different regions of a medium; passing through points at which the density is equal; as, an isopycnic line or surface.

I`so*pyc"nic, n. (Physics) A line or surface passing through those points in a medium, at which the density is the same.

I*sor"cin (?), n. [Iso- + orcin.] (Chem.) A crystalline hydrocarbon derivative, metameric with orcin, but produced artificially; -- called also cresorcin.

I`sor*rop"ic (?), a. [Gr. 'iso`rropos in equipoise; 'i`sos equal + "roph` downward inclination or momentum.] Of equal value.

Isorropic line (in a diagram) (Geom.), the locus of all the points for which a specified function has a constant value. Newcomb.

I*sos"ce*les (?), a. [L., fr. Gr. &?;; 'i`sos equal + &?; leg.] (Geom.) Having two legs or sides that are equal; -- said of a triangle.

||I`so*spon"dy*li (?), n. pl. [NL., fr. Gr. 'i`sos equal + &?;, &?;, a ||vertebra.] (Zoöl.) An extensive order of fishes, including the ||salmons, herrings, and many allied forms. || I`so*spon"dy*lous (?), a. (Zoöl.) Of or pertaining to the Isospondyli; having the anterior vertebræ separate and normal.