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　　Butwhythisshouldbealawofnatureifeachspecieshasbeenindependentlycreated，nomancanexplain。

　　Manyotherfactsare，asitseemstome，explicableonthistheory。

　　Howstrangeitisthatabird，undertheformofwoodpecker，shouldhavebeencreatedtopreyoninsectsontheground。thatuplandgeese，whichneverorrarelyswim，shouldhavebeencreatedwithwebbedfeet。thatathrushshouldhavebeencreatedtodiveandfeedonsub-aquaticinsects。

　　andthatapetrelshouldhavebeencreatedwithhabitsandstructurefittingitforthelifeofanaukorgrebe！andsooninendlessothercases。Butontheviewofeachspeciesconstantlytryingtoincreaseinnumber，withnaturalselectionalwaysreadytoadapttheslowlyvaryingdescendantsofeachtoanyunoccupiedorill-occupiedplaceinnature，thesefactsceasetobestrange，orperhapsmightevenhavebeenanticipated。

　　Asnaturalselectionactsbycompetition，itadaptstheinhabitantsofeachcountryonlyinrelationtothedegreeofperfectionoftheirassociates。

　　sothatweneedfeelnosurpriseattheinhabitantsofanyonecountry，althoughontheordinaryviewsupposedtohavebeenspeciallycreatedandadaptedforthatcountry，beingbeatenandsupplantedbythenaturalisedproductionsfromanotherland。Noroughtwetomarvelifallthecontrivancesinnaturebenot，asfaraswecanjudge，absolutelyperfect。andifsomeofthembeabhorrenttoourideasoffitness。Weneednotmarvelatthestingofthebeecausingthebee’sowndeath。atdronesbeingproducedinsuchvastnumbersforonesingleact，andbeingthenslaughteredbytheirsterilesisters。attheastonishingwasteofpollenbyourfir-trees。

　　attheinstinctivehatredofthequeenbeeforherownfertiledaughters。

　　atichneumonidaefeedingwithinthelivebodiesofcaterpillars。andatothersuchcases。Thewonderindeedis，onthetheoryofnaturalselection，thatmorecasesofthewantofabsoluteperfectionhavenotbeenobserved。

　　Thecomplexandlittleknownlawsgoverningvariationarethesame，asfaraswecansee，withthelawswhichhavegovernedtheproductionofso-calledspecificforms。Inbothcasesphysicalconditionsseemtohaveproducedbutlittledirecteffect。yetwhenvarietiesenteranyzone，theyoccasionallyassumesomeofthecharactersofthespeciespropertothatzone。Inbothvarietiesandspecies，useanddisuseseemtohaveproducedsomeeffect。foritisdifficulttoresistthisconclusionwhenwelook，forinstance，atthelogger-headedduck，whichhaswingsincapableofflight，innearlythesameconditionasinthedomesticduck。orwhenwelookattheburrowingtucutucu，whichisoccasionallyblind，andthenatcertainmoles，whicharehabituallyblindandhavetheireyescoveredwithskin。

　　orwhenwelookattheblindanimalsinhabitingthedarkcavesofAmericaandEurope。Inbothvarietiesandspeciescorrectionofgrowthseemstohaveplayedamostimportantpart，sothatwhenoneparthasbeenmodifiedotherpartsarenecessarilymodified。Inbothvarietiesandspeciesreversionstolong-lostcharactersoccur。Howinexplicableonthetheoryofcreationistheoccasionalappearanceofstripesontheshoulderandlegsoftheseveralspeciesofthehorse-genusandintheirhybrids！Howsimplyisthisfactexplainedifwebelievethatthesespecieshavedescendedfromastripedprogenitor，inthesamemannerastheseveraldomesticbreedsofpigeonhavedescendedfromtheblueandbarredrock-pigeon！

　　Ontheordinaryviewofeachspecieshavingbeenindependentlycreated，whyshouldthespecificcharacters，orthosebywhichthespeciesofthesamegenusdifferfromeachother，bemorevariablethanthegenericcharactersinwhichtheyallagree？Why，forinstance，shouldthecolourofaflowerbemorelikelytovaryinanyonespeciesofagenus，iftheotherspecies，supposedtohavebeencreatedindependently，havedifferentlycolouredflowers，thanifallthespeciesofthegenushavethesamecolouredflowers？

　　Ifspeciesareonlywell-markedvarieties，ofwhichthecharactershavebecomeinahighdegreepermanent，wecanunderstandthisfact。fortheyhavealreadyvariedsincetheybranchedofffromacommonprogenitorincertaincharacters，bywhichtheyhavecometobespecificallydistinctfromeachother。andthereforethesesamecharacterswouldbemorelikelystilltobevariablethanthegenericcharacterswhichhavebeeninheritedwithoutchangeforanenormousperiod。Itisinexplicableonthetheoryofcreationwhyapartdevelopedinaveryunusualmannerinanyonespeciesofagenus，andtherefore，aswemaynaturallyinfer，ofgreatimportancetothespecies，shouldbeeminentlyliabletovariation。but，onmyview，thisparthasundergone，sincetheseveralspeciesbranchedofffromacommonprogenitor，anunusualamountofvariabilityandmodification，andthereforewemightexpectthispartgenerallytobestillvariable。Butapartmaybedevelopedinthemostunusualmanner，likethewingofabat，andyetnotbemorevariablethananyotherstructure，ifthepartbecommontomanysubordinateforms，thatis，ifithasbeeninheritedforaverylongperiod。forinthiscaseitwillhavebeenrenderedconstantbylong-continuednaturalselection。

　　Glancingatinstincts，marvellousassomeare，theyoffernogreaterdifficultythandoescorporealstructureonthetheoryofthenaturalselectionofsuccessive，slight，butprofitablemodifications。Wecanthusunderstandwhynaturemovesbygraduatedstepsinendowingdifferentanimalsofthesameclasswiththeirseveralinstincts。Ihaveattemptedtoshowhowmuchlighttheprincipleofgradationthrowsontheadmirablearchitecturalpowersofthehive-bee。Habitnodoubtsometimescomesintoplayinmodifyinginstincts。butitcertainlyisnotindispensable，aswesee，inthecaseofneuterinsects，whichleavenoprogenytoinherittheeffectsoflong-continuedhabit。Ontheviewofallthespeciesofthesamegenushavingdescendedfromacommonparent，andhavinginheritedmuchincommon，wecanunderstandhowitisthatalliedspecies，whenplacedunderconsiderablydifferentconditionsoflife，yetshouldfollownearlythesameinstincts。whythethrushofSouthAmerica，forinstance，lineshernestwithmudlikeourBritishspecies。Ontheviewofinstinctshavingbeenslowlyacquiredthroughnaturalselectionweneednotmarvelatsomeinstinctsbeingapparentlynotperfectandliabletomistakes，andatmanyinstinctscausingotheranimalstosuffer。

　　Ifspeciesbeonlywell-markedandpermanentvarieties，wecanatonceseewhytheircrossedoffspringshouldfollowthesamecomplexlawsintheirdegreesandkindsofresemblancetotheirparents，——inbeingabsorbedintoeachotherbysuccessivecrosses，andinothersuchpoints，——asdothecrossedoffspringofacknowledgedvarieties。Ontheotherhand，thesewouldbestrangefactsifspecieshavebeenindependentlycreated，andvarietieshavebeenproducedbysecondarylaws。

　　Ifweadmitthatthegeologicalrecordisimperfectinanextremedegree，thensuchfactsastherecordgives，supportthetheoryofdescentwithmodification。Newspecieshavecomeonthestageslowlyandatsuccessiveintervals。andtheamountofchange，afterequalintervalsoftime，iswidelydifferentindifferentgroups。Theextinctionofspeciesandofwholegroupsofspecies，whichhasplayedsoconspicuousapartinthehistoryoftheorganicworld，almostinevitablyfollowsontheprincipleofnaturalselection。foroldformswillbesupplantedbynewandimprovedforms。Neithersinglespeciesnorgroupsofspeciesreappearwhenthechainofordinarygenerationhasoncebeenbroken。Thegradualdiffusionofdominantforms，withtheslowmodificationoftheirdescendants，causestheformsoflife，afterlongintervalsoftime，toappearasiftheyhadchangedsimultaneouslythroughouttheworld。Thefactofthefossilremainsofeachformationbeinginsomedegreeintermediateincharacterbetweenthefossilsintheformationsaboveandbelow，issimplyexplainedbytheirintermediatepositioninthechainofdescent。Thegrandfactthatallextinctorganicbeingsbelongtothesamesystemwithrecentbeings，fallingeitherintothesameorintointermediategroups，followsfromthelivingandtheextinctbeingtheoffspringofcommonparents。Asthegroupswhichhavedescendedfromanancientprogenitorhavegenerallydivergedincharacter，theprogenitorwithitsearlydescendantswilloftenbeintermediateincharacterincomparisonwithitslaterdescendants。andthuswecanseewhythemoreancientafossilis，theofteneritstandsinsomedegreeintermediatebetweenexistingandalliedgroups。Recentformsaregenerallylookedatasbeing，insomevaguesense，higherthanancientandextinctforms。andtheyareinsofarhigherasthelaterandmoreimprovedformshaveconqueredtheolderandlessimprovedorganicbeingsinthestruggleforlife。Lastly，thelawofthen=’448’>longenduranceofalliedformsonthesamecontinent，&amp。mdash。ofmarsupialsinAustralia，ofedentatainAmerica，andothersuchcases，——isintelligible，forwithinaconfinedcountry，therecentandtheextinctwillnaturallybealliedbydescent。

　　Lookingtogeographicaldistribution，ifweadmitthattherehasbeenduringthelongcourseofagesmuchmigrationfromonepartoftheworldtoanother，owingtoformerclimatalandgeographicalchangesandtothemanyoccasionalandunknownmeansofdispersal，thenwecanunderstand，onthetheoryofdescentwithmodification，mostofthegreatleadingfactsinDistribution。Wecanseewhythereshouldbesostrikingaparallelisminthedistributionoforganicbeingsthroughoutspace，andintheirgeologicalsuccessionthroughouttime。forinbothcasesthebeingshavebeenconnectedbythebondofordinarygeneration，andthemeansofmodificationhavebeenthesame。Weseethefullmeaningofthewonderfulfact，whichmusthavestruckeverytraveller，namely，thatonthesamecontinent，underthemostdiverseconditions，underheatandcold，onmountainandlowland，ondesertsandmarshes，mostoftheinhabitantswithineachgreatclassareplainlyrelated。fortheywillgenerallybedescendantsofthesameprogenitorsandearlycolonists。Onthissameprincipleofformermigration，combinedinmostcaseswithmodification，wecanunderstand，bytheaidoftheGlacialperiod，theidentityofsomefewplants，andthecloseallianceofmanyothers，onthemostdistantmountains，underthemostdifferentclimates。andlikewisethecloseallianceofsomeoftheinhabitantsoftheseainthenorthernandsoutherntemperatezones，thoughseparatedbythewholeintertropicalocean。Althoughtwoareasmaypresentthesamephysicalconditionsoflife，weneedfeelnosurpriseattheirinhabitantsbeingwidelydifferent，iftheyhavebeenforalongperiodcompletelyseparatedfromeachother。forastherelationoforganismtoorganismisthemostimportantofallrelations，andasthetwoareaswillhavereceivedcolonistsfromsomethirdsourceorfromeachother，atvariousperiodsandindifferentproportions，thecourseofmodificationinthetwoareaswillinevitablybedifferent。

　　Onthisviewofmigration，withsubsequentmodification，wecanseewhyoceanicislandsshouldbeinhabitedbyfewspecies，butofthese，thatmanyshouldbepeculiar。Wecanclearlyseewhythoseanimalswhichcannotcrosswidespacesofocean，asfrogsandterrestrialmammals，shouldnotinhabitoceanicislands。andwhy，ontheotherhand，newandpeculiarspeciesofbats，whichcantraversetheocean，shouldsooftenbefoundonislandsfardistantfromanycontinent。Suchfactsasthepresenceofpeculiarspeciesofbats，andtheabsenceofallothermammals，onoceanicislands，areutterlyinexplicableonthetheoryofindependentactsofcreation。

　　Theexistenceofcloselyalliedorrepresentativespeciesinanytwoareas，implies，onthetheoryofdescentwithmodification，thatthesameparentsformerlyinhabitedbothareas。andwealmostinvariablyfindthatwherevermanycloselyalliedspeciesinhabittwoareas，someidenticalspeciescommontobothstillexist。Wherevermanycloselyalliedyetdistinctspeciesoccur，manydoubtfulformsandvarietiesofthesamespecieslikewiseoccur。Itisaruleofhighgeneralitythattheinhabitantsofeachareaarerelatedtotheinhabitantsofthenearestsourcewhenceimmigrantsmighthavebeenderived。WeseethisinnearlyalltheplantsandanimalsoftheGalapagosarchipelago，ofJuanFernandez，andoftheotherAmericanislandsbeingrelatedinthemoststrikingmannertotheplantsandanimalsoftheneighbouringAmericanmainland。andthoseoftheCapedeVerdearchipelagoandotherAfricanislandstotheAfricanmainland。Itmustbeadmittedthatthesefactsreceivenoexplanationonthetheoryofcreation。

　　Thefact，aswehaveseen，thatallpastandpresentorganicbeingsconstituteonegrandnaturalsystem，withgroupsubordinatetogroup，andwithextinctgroupsoftenfallinginbetweenrecentgroups，isintelligibleonthetheoryofnaturalselectionwithitscontingenciesofextinctionanddivergenceofcharacter。Onthesesameprinciplesweseehowitis，thatthemutualaffinitiesofthespeciesandgenerawithineachclassaresocomplexandcircuitous。Weseewhycertaincharactersarefarmoreserviceablethanothersforclassification——whyadaptivecharacters，thoughofparamountimportancetothebeing，areofhardlyanyimportanceinclassification。whycharactersderivedfromrudimentaryparts，thoughofnoservicetothebeing，areoftenofhighclassificatoryvalue。andwhyembryologicalcharactersarethemostvaluableofall。Therealaffinitiesofallorganicbeingsareduetoinheritanceorcommunityofdescent。Thenaturalsystemisagenealogicalarrangement，inwhichwehavetodiscoverthelinesofdescentbythemostpermanentcharacters，howeverslighttheirvitalimportancemaybe。

　　Theframeworkofbonesbeingthesameinthehandofaman，wingofabat，finoftheporpoise，andlegofthehorse，——thesamenumberofvertebraeformingtheneckofthegiraffeandoftheelephant，——andinnumerableothersuchfacts，atonceexplainthemselvesonthetheoryofdescentwithslowandslightsuccessivemodifications。Thesimilarityofpatterninthewingandlegofabat，thoughusedforsuchdifferentpurposes，——

　　inthejawsandlegsofacrab，——inthepetals，stamens，andpistilsofaflower，islikewiseintelligibleontheviewofthegradualmodificationofpartsororgans，whichwerealikeintheearlyprogenitorofeachclass。

　　Ontheprincipleofsuccessivevariationsnotalwayssuperveningatanearlyage，andbeinginheritedatacorrespondingnotearlyperiodoflife，wecanclearlyseewhytheembryosofmammals，birds，reptiles，andfishesshouldbesocloselyalike，andshouldbesounliketheadultforms。Wemayceasemarvellingattheembryoofanair-breathingmammalorbirdhavingbranchialslitsandarteriesrunninginloops，likethoseinafishwhichhastobreathetheairdissolvedinwater，bytheaidofwell-developedbranchiae。

　　Disuse，aidedsometimesbynaturalselection，willoftentendtoreduceanorgan，whenithasbecomeuselessbychangedhabitsorunderchangedconditionsoflife。andwecanclearlyunderstandonthisviewthemeaningofrudimentaryorgans。Butdisuseandselectionwillgenerallyactoneachcreature，whenithascometomaturityandhastoplayitsfullpartinthestruggleforexistence，andwillthushavelittlepowerofactingonanorganduringearlylife。hencetheorganwillnotbemuchreducedorrenderedrudimentaryatthisearlyage。Thecalf，forinstance，hasinheritedteeth，whichnevercutthroughthegumsoftheupperjaw，fromanearlyprogenitorhavingwell-developedteeth。andwemaybelieve，thattheteethinthematureanimalwerereduced，duringsuccessivegenerations，bydisuseorbythetongueandpalatehavingbeenfittedbynaturalselectiontobrowsewithouttheiraid。whereasinthecalf，theteethhavebeenleftuntouchedbyselectionordisuse，andontheprincipleofinheritanceatcorrespondingageshavebeeninheritedfromaremoteperiodtothepresentday。Ontheviewofeachorganicbeingandeachseparateorganhavingbeenspeciallycreated，howutterlyinexplicableitisthatparts，liketheteethintheembryoniccalforliketheshrivelledwingsunderthesolderedwing-coversofsomebeetles，shouldthussofrequentlybeartheplainstampofinutility！Naturemaybesaidtohavetakenpainstoreveal，byrudimentaryorgansandbyhomologousstructures，herschemeofmodification，whichitseemsthatwewilfullywillnotunderstand。

　　Ihavenowrecapitulatedthechieffactsandconsiderationswhichhavethoroughlyconvincedmethatspecieshavechanged，andarestillslowlychangingbythepreservationandaccumulationofsuccessiveslightfavourablevariations。Why，itmaybeasked，haveallthemosteminentlivingnaturalistsandgeologistsrejectedthisviewofthemutabilityofspecies？Itcannotbeassertedthatorganicbeingsinastateofnaturearesubjecttonovariation。itcannotbeprovedthattheamountofvariationinthecourseoflongagesisalimitedquantity。nocleardistinctionhasbeen，orcanbe，drawnbetweenspeciesandwell-markedvarieties。Itcannotbemaintainedthatspecieswhenintercrossedareinvariablysterile，andvarietiesinvariablyfertile。orthatsterilityisaspecialendowmentandsignofcreation。

　　Thebeliefthatspecieswereimmutableproductionswasalmostunavoidableaslongasthehistoryoftheworldwasthoughttobeofshortduration。

　　andnowthatwehaveacquiredsomeideaofthelapseoftime，wearetooapttoassume，withoutproof，thatthegeologicalrecordissoperfectthatitwouldhaveaffordedusplainevidenceofthemutationofspecies，iftheyhadundergonemutation。

　　Butthechiefcauseofournaturalunwillingnesstoadmitthatonespecieshasgivenbirthtootheranddistinctspecies，isthatwearealwaysslowinadmittinganygreatchangeofwhichwedonotseetheintermediatesteps。

　　Thedifficultyisthesameasthatfeltbysomanygeologists，whenLyellfirstinsistedthatlonglinesofinlandcliffshadbeenformed，andgreatvalleysexcavated，bytheslowactionofthecoast-waves。Themindcannotpossiblygraspthefullmeaningofthetermofahundredmillionyears。

　　itcannotaddupandperceivethefulleffectsofmanyslightvariations，accumulatedduringanalmostinfinitenumberofgenerations。

　　AlthoughIamfullyconvincedofthetruthoftheviewsgiveninthisvolumeundertheformofanabstract，Ibynomeansexpecttoconvinceexperiencednaturalistswhosemindsarestockedwithamultitudeoffactsallviewed，duringalongcourseofyears，fromapointofviewdirectlyoppositetomine。Itissoeasytohideourignoranceundersuchexpressionsasthe`planofcreation，’`unityofdesign，’&amp。c。，andtothinkthatwegiveanexplanationwhenweonlyrestateafact。Anyonewhosedispositionleadshimtoattachmoreweighttounexplaineddifficultiesthantotheexplanationofacertainnumberoffactswillcertainlyrejectmytheory。

　　Afewnaturalists，endowedwithmuchflexibilityofmind，andwhohavealreadybeguntodoubtontheimmutabilityofspecies，maybeinfluencedbythisvolume。butIlookwithconfidencetothefuture，toyoungandrisingnaturalists，whowillbeabletoviewbothsidesofthequestionwithimpartiality。Whoeverisledtobelievethatspeciesaremutablewilldogoodservicebyconscientiouslyexpressinghisconviction。foronlythuscantheloadofprejudicebywhichthissubjectisoverwhelmedberemoved。

　　Severaleminentnaturalistshaveoflatepublishedtheirbeliefthatamultitudeofreputedspeciesineachgenusarenotrealspecies。butthatotherspeciesarereal，thatis，havebeenindependentlycreated。

　　Thisseemstomeastrangeconclusiontoarriveat。Theyadmitthatamultitudeofforms，whichtilllatelytheythemselvesthoughtwerespecialcreations，andwhicharestillthuslookedatbythemajorityofnaturalists，andwhichconsequentlyhaveeveryexternalcharacteristicfeatureoftruespecies，——theyadmitthatthesehavebeenproducedbyvariation，buttheyrefusetoextendthesameviewtootherandveryslightlydifferentforms。Neverthelesstheydonotpretendthattheycandefine，orevenconjecture，whicharethecreatedformsoflife，andwhicharethoseproducedbysecondarylaws。

　　Theyadmitvariationasaveracausainonecase，theyarbitrarilyrejectitinanother，withoutassigninganydistinctioninthetwocases。

　　Thedaywillcomewhenthiswillbegivenasacuriousillustrationoftheblindnessofpreconceivedopinion。Theseauthorsseemnomorestartledatamiraculousactofcreationthanatanordinarybirth。Butdotheyreallybelievethatatinnumerableperiodsintheearth’shistorycertainelementalatomshavebeencommandedsuddenlytoflashintolivingtissues？

　　Dotheybelievethatateachsupposedactofcreationoneindividualormanywereproduced？Werealltheinfinitelynumerouskindsofanimalsandplantscreatedaseggsorseed，orasfullgrown？andinthecaseofmammals，weretheycreatedbearingthefalsemarksofnourishmentfromthemother’swomb？Althoughnaturalistsveryproperlydemandafullexplanationofeverydifficultyfromthosewhobelieveinthemutabilityofspecies，ontheirownsidetheyignorethewholesubjectofthefirstappearanceofspeciesinwhattheyconsiderreverentsilence。

　　ItmaybeaskedhowfarIextendthedoctrineofthemodificationofspecies。Thequestionisdifficulttoanswer，becausethemoredistincttheformsarewhichwemayconsider，bysomuchtheargumentsfallawayinforce。Butsomeargumentsofthegreatestweightextendveryfar。Allthemembersofwholeclassescanbeconnectedtogetherbychainsofaffinities，andallcanbeclassifiedonthesameprinciple，ingroupssubordinatetogroups。Fossilremainssometimestendtofillupverywideintervalsbetweenexistingorders。Organsinarudimentaryconditionplainlyshowthatanearlyprogenitorhadtheorganinafullydevelopedstate。andthisinsomeinstancesnecessarilyimpliesanenormousamountofmodificationinthedescendants。Throughoutwholeclassesvariousstructuresareformedonthesamepattern，andatanembryonicagethespeciescloselyresembleeachother。ThereforeIcannotdoubtthatthetheoryofdescentwithmodificationembracesallthemembersofthesameclass。Ibelievethatanimalshavedescendedfromatmostonlyfourorfiveprogenitors，andplantsfromanequalorlessernumber。

　　Analogywouldleadmeonestepfurther，namely，tothebeliefthatallanimalsandplantshavedescendedfromsomeoneprototype。Butanalogymaybeadeceitfulguide。Neverthelessalllivingthingshavemuchincommon，intheirchemicalcomposition，theirgerminalvesicles，theircellularstructure，andtheirlawsofgrowthandreproduction。Weseethiseveninsotriflingacircumstanceasthatthesamepoisonoftensimilarlyaffectsplantsandanimals。orthatthepoisonsecretedbythegall-flyproducesmonstrousgrowthsonthewildroseoroak-tree。ThereforeIshouldinferfromanalogythatprobablyalltheorganicbeingswhichhaveeverlivedonthisearthhavedescendedfromsomeoneprimordialform，intowhichlifewasfirstbreathed。

　　Whentheviewsentertainedinthisvolumeontheoriginofspecies，orwhenanalogousviewsaregenerallyadmitted，wecandimlyforeseethattherewillbeaconsiderablerevolutioninnaturalhistory。Systematistswillbeabletopursuetheirlaboursasatpresent。buttheywillnotbeincessantlyhauntedbytheshadowydoubtwhetherthisorthatformbeinessenceaspecies。ThisIfeelsure，andIspeakafterexperience，willbenoslightrelief。TheendlessdisputeswhetherornotsomefiftyspeciesofBritishbramblesaretruespecieswillcease。Systematistswillhaveonlytodecidenotthatthiswillbeeasywhetheranyformbesufficientlyconstantanddistinctfromotherforms，tobecapableofdefinition。andifdefinable，whetherthedifferencesbesufficientlyimportanttodeserveaspecificname。Thislatterpointwillbecomeafarmoreessentialconsiderationthanitisatpresent。fordifferences，howeverslight，betweenanytwoforms，ifnotblendedbyintermediategradations，arelookedatbymostnaturalistsassufficienttoraisebothformstotherankofspecies。Hereafterweshallbecompelledtoacknowledgethattheonlydistinctionbetweenspeciesandwell-markedvarietiesis，thatthelatterareknown，orbelieved，tobeconnectedatthepresentdaybyintermediategradations，whereasspecieswereformerlythusconnected。Hence，withoutquiterejectingtheconsiderationofthepresentexistenceofintermediategradationsbetweenanytwoforms，weshallbeledtoweighmorecarefullyandtovaluehighertheactualamountofdifferencebetweenthem。Itisquitepossiblethatformsnowgenerallyacknowledgedtobemerelyvarietiesmayhereafterbethoughtworthyofspecificnames，aswiththeprimroseandcowslip。andinthiscasescientificandcommonlanguagewillcomeintoaccordance。

　　Inshort，weshallhavetotreatspeciesinthesamemannerasthosenaturaliststreatgenera，whoadmitthatgeneraaremerelyartificialcombinationsmadeforconvenience。Thismaynotbeacheeringprospect。butweshallatleastbefreedfromthevainsearchfortheundiscoveredandundiscoverableessenceofthetermspecies。

　　Theotherandmoregeneraldepartmentsofnaturalhistorywillrisegreatlyininterest。Thetermsusedbynaturalistsofaffinity，relationship，communityoftype，paternity，morphology，adaptivecharacters，rudimentaryandabortedorgans，&amp。c。，willceasetobemetaphorical，andwillhaveaplainsignification。Whenwenolongerlookatanorganicbeingasasavagelooksataship，asatsomethingwhollybeyondhiscomprehension。

　　whenweregardeveryproductionofnatureasonewhichhashadahistory。

　　whenwecontemplateeverycomplexstructureandinstinctasthesummingupofmanycontrivances，eachusefultothepossessor，nearlyinthesamewayaswhenwelookatanygreatmechanicalinventionasthesummingupofthelabour，theexperience，thereason，andeventheblundersofnumerousworkmen。whenwethusvieweachorganicbeing，howfarmoreinteresting，Ispeakfromexperience，willthestudyofnaturalhistorybecome！

　　Agrandandalmostuntroddenfieldofinquirywillbeopened，onthecausesandlawsofvariation，oncorrelationofgrowth，ontheeffectsofuseanddisuse，onthedirectactionofexternalconditions，andsoforth。Thestudyofdomesticproductionswillriseimmenselyinvalue。

　　Anewvarietyraisedbymanwillbeafarmoreimportantandinterestingsubjectforstudythanonemorespeciesaddedtotheinfinitudeofalreadyrecordedspecies。Ourclassificationswillcometobe，asfarastheycanbesomade，genealogies。andwillthentrulygivewhatmaybecalledtheplanofcreation。Therulesforclassifyingwillnodoubtbecomesimplerwhenwehaveadefiniteobjectinview。Wepossessnopedigreesorarmorialbearings。andwehavetodiscoverandtracethemanydiverginglinesofdescentinournaturalgenealogies，bycharactersofanykindwhichhavelongbeeninherited。Rudimentaryorganswillspeakinfalliblywithrespecttothenatureoflong-loststructures。Speciesandgroupsofspecies，whicharecalledaberrant，andwhichmayfancifullybecalledlivingfossils，willaidusinformingapictureoftheancientformsoflife。Embryologywillrevealtousthestructure，insomedegreeobscured，oftheprototypesofeachgreatclass。

　　Whenwecanfeelassuredthatalltheindividualsofthesamespecies，andallthecloselyalliedspeciesofmostgenera，havewithinanotveryremoteperioddescendedfromoneparent，andhavemigratedfromsomeonebirthplace。andwhenwebetterknowthemanymeansofmigration，then，bythelightwhichgeologynowthrows，andwillcontinuetothrow，onformerchangesofclimateandoftheleveloftheland，weshallsurelybeenabledtotraceinanadmirablemannertheformermigrationsoftheinhabitantsofthewholeworld。Evenatpresent，bycomparingthedifferencesoftheinhabitantsoftheseaontheoppositesidesofacontinent，andthenatureofthevariousinhabitantsofthatcontinentinrelationtotheirapparentmeansofimmigration，somelightcanbethrownonancientgeography。

　　ThenoblescienceofGeologylosesgloryfromtheextremeimperfectionoftherecord。Thecrustoftheearthwithitsembeddedremainsmustnotbelookedatasawell-filledmuseum，butasapoorcollectionmadeathazardandatrareintervals。Theaccumulationofeachgreatfossiliferousformationwillberecognisedashavingdependedonanunusualconcurrenceofcircumstances，andtheblankintervalsbetweenthesuccessivestagesashavingbeenofvastduration。Butweshallbeabletogaugewithsomesecuritythedurationoftheseintervalsbyacomparisonoftheprecedingandsucceedingorganicforms。Wemustbecautiousinattemptingtocorrelateasstrictlycontemporaneoustwoformations，whichincludefewidenticalspecies，bythegeneralsuccessionoftheirformsoflife。Asspeciesareproducedandexterminatedbyslowlyactingandstillexistingcauses，andnotbymiraculousactsofcreationandbycatastrophes。andasthemostimportantofallcausesoforganicchangeisonewhichisalmostindependentofalteredandperhapssuddenlyalteredphysicalconditions，namely，themutualrelationoforganismtoorganism，——theimprovementofonebeingentailingtheimprovementortheexterminationofothers。itfollows，thattheamountoforganicchangeinthefossilsofconsecutiveformationsprobablyservesasafairmeasureofthelapseofactualtime。Anumberofspecies，however，keepinginabodymightremainforalongperiodunchanged，whilstwithinthissameperiod，severalofthesespecies，bymigratingintonewcountriesandcomingintocompetitionwithforeignassociates，mightbecomemodified。sothatwemustnotoverratetheaccuracyoforganicchangeasameasureoftime。Duringearlyperiodsoftheearth’shistory，whentheformsoflifewereprobablyfewerandsimpler，therateofchangewasprobablyslower。andatthefirstdawnoflife，whenveryfewformsofthesimpleststructureexisted，therateofchangemayhavebeenslowinanextremedegree。Thewholehistoryoftheworld，asatpresentknown，althoughofalengthquiteincomprehensiblebyus，willhereafterberecognisedasamerefragmentoftime，comparedwiththeageswhichhaveelapsedsincethefirstcreature，theprogenitorofinnumerableextinctandlivingdescendants，wascreated。

　　InthedistantfutureIseeopenfieldsforfarmoreimportantresearches。

　　Psychologywillbebasedonanewfoundation，thatofthenecessaryacquirementofeachmentalpowerandcapacitybygradation。Lightwillbethrownontheoriginofmanandhishistory。

　　Authorsofthehighesteminenceseemtobefullysatisfiedwiththeviewthateachspecieshasbeenindependentlycreated。TomyminditaccordsbetterwithwhatweknowofthelawsimpressedonmatterbytheCreator，thattheproductionandextinctionofthepastandpresentinhabitantsoftheworldshouldhavebeenduetosecondarycauses，likethosedeterminingthebirthanddeathoftheindividual。WhenIviewallbeingsnotasspecialcreations，butasthelinealdescendantsofsomefewbeingswhichlivedlongbeforethefirstbedoftheSiluriansystemwasdeposited，theyseemtometobecomeennobled。Judgingfromthepast，wemaysafelyinferthatnotonelivingspecieswilltransmititsunalteredlikenesstoadistantfuturity。Andofthespeciesnowlivingveryfewwilltransmitprogenyofanykindtoafardistantfuturity。forthemannerinwhichallorganicbeingsaregrouped，showsthatthegreaternumberofspeciesofeachgenus，andallthespeciesofmanygenera，haveleftnodescendants，buthavebecomeutterlyextinct。Wecansofartakeapropheticglanceintofuturityastoforetelthatitwillbethecommonandwidely-spreadspecies，belongingtothelargeranddominantgroups，whichwillultimatelyprevailandprocreatenewanddominantspecies。AsallthelivingformsoflifearethelinealdescendantsofthosewhichlivedlongbeforetheSilurianepoch，wemayfeelcertainthattheordinarysuccessionbygenerationhasneveroncebeenbroken，andthatnocataclysmhasdesolatedthewholeworld。Hencewemaylookwithsomeconfidencetoasecurefutureofequallyinappreciablelength。Andasnaturalselectionworkssolelybyandforthegoodofeachbeing，allcorporealandmentalendowmentswilltendtoprogresstowardsperfection。

　　Itisinterestingtocontemplateanentangledbank，clothedwithmanyplantsofmanykinds，withbirdssingingonthebushes，withvariousinsectsflittingabout，andwithwormscrawlingthroughthedampearth，andtoreflectthattheseelaboratelyconstructedforms，sodifferentfromeachother，anddependentoneachotherinsocomplexamanner，haveallbeenproducedbylawsactingaroundus。Theselaws，takeninthelargestsense，beingGrowthwithReproduction。inheritancewhichisalmostimpliedbyreproduction。Variabilityfromtheindirectanddirectactionoftheexternalconditionsoflife，andfromuseanddisuse。aRatioofIncreasesohighastoleadtoaStruggleforLife，andasaconsequencetoNaturalSelection，entailingDivergenceofCharacterandtheExtinctionofless-improvedforms。

　　Thus，fromthewarofnature，fromfamineanddeath，themostexaltedobjectwhichwearecapableofconceiving，namely，theproductionofthehigheranimals，directlyfollows。Thereisgrandeurinthisviewoflife，withitsseveralpowers，havingbeenoriginallybreathedintoafewformsorintoone。andthat，whilstthisplanethasgonecyclingonaccordingtothefixedlawofgravity，fromsosimpleabeginningendlessformsmostbeautifulandmostwonderfulhavebeen，andarebeing，evolved。PreviousChapterCharlesDarwin-TheOriginofSpeciesTheOriginofSpeciesbyCharlesDarwinGlossaryIamindebtedtothekindnessofMr。W。S。DallasforthisGlossary，whichhasbeengivenbecauseseveralreadershavecomplainedtomethatsomeofthetermsusedwereunintelligibletothem。Mr。Dallashasendeavouredtogivetheexplanationsofthetermsinaspopularaformaspossible。EDITOR’SNOTE：ThisglossarydidnotappearinthefirsteditionandhasbeenreproducedheredirectlyfromthesixtheditionABERRANTFormsorgroupsofanimalsorplantswhichdeviateinimportantcharactersfromtheirnearestallies，soasnottobeeasilyincludedinthesamegroupwiththem，aresaidtobeaberrant。ABERRATION

　　inOpticsIntherefractionoflightbyaconvexlenstherayspassingthroughdifferentpartsofthelensarebroughttoafocusatslightlydifferentdistances，thisiscalledsphericalaberration。atthesametimethecolouredraysareseparatedbytheprismaticactionofthelensandlikewisebroughttoafocusatdifferentdistances，thisischromaticaberration。ABNORMALContrarytothegeneralrule。ABORTEDAnorganissaidtobeaborted，whenitsdevelopmenthasbeenarrestedataveryearlystage。ALBINISMAlbinosareanimalsinwhichtheusualcolouringmatterscharacteristicofthespecieshavenotbeenproducedintheskinanditsappendages。Albinismisthestateofbeinganalbino。ALGAEAclassofplantsincludingtheordinarysea-weedsandthefilamentousfresh-waterweeds。ALTERNATION

　　OFGENERATIONSThistermisappliedtoapeculiarmodeofreproductionwhichprevailsamongmanyoftheloweranimals，inwhichtheeggproducesalivingformquitedifferentfromitsparent，butfromwhichtheparent-formisreproducedbyaprocessofbudding，orbythedivisionofthesubstanceofthefirstproductoftheegg。AMMONITESAgroupoffossil，spiral，chamberedshells，alliedtotheexistingpearlyNautilus，buthavingthepartitionsbetweenthechamberswavedincomplicatedpatternsattheirjunctionwiththeouterwalloftheshell。ANALOGYThatresemblanceofstructureswhichdependsuponsimilarityoffunction，asinthewingsofinsectsandbirds。Suchstructuresaresaidtobeanalogous，andtobeanaloguesofeachother。ANIMALCULEAminuteanimal：generallyappliedtothosevisibleonlybythemicroscope。ANNELIDSAclassofwormsinwhichthesurfaceofthebodyexhibitsamoreorlessdistinctdivisionintoringsorsegments，generallyprovidedwithappendagesforlocomotionandwithgills。Itincludestheordinarymarineworms，theearthworms，andtheleeches。ANTENN&AElig。JointedorgansappendedtotheheadinInsects，CrustaceaandCentipedes，andnotbelongingtothemouth。ANTHERSThesummitsofthestamensofflowers，inwhichthepollenorfertilisingdustisproduced。APLACENTALIA，APLACENTATAorAplacentalMammalsSeeMammalia。ARCHETYPALOforbelongingtotheArchetype，oridealprimitiveformuponwhichallthebeingsofagroupseemtobeorganised。ARTICULATAAgreatdivisionoftheAnimalKingdomcharacterisedgenerallybyhavingthesurfaceofthebodydividedintoringscalledsegments，agreaterorlessnumberofwhicharefurnishedwithjointedlegssuchasInsects，CrustaceansandCentipedes。ASYMMETRICALHavingthetwosidesunlike。ATROPHIEDArrestedindevelopmentataveryearlystage。BALANUSThegenusincludingthecommonAcorn-shellswhichliveinabundanceontherocksofthesea-coast。BATRACHIANSAclassofanimalsalliedtotheReptiles，butundergoingapeculiarmetamorphosis，inwhichtheyounganimalisgenerallyaquaticandbreathesbygills。Examples，Frogs，Toads，andNewts。BOULDERSLargetransportedblocksofstonegenerallyimbeddedinclaysorgravels。BRACHIOPODAAclassofmarineMollusca，orsoft-bodiedanimals，furnishedwithabivalveshell，attachedtosubmarineobjectsbyastalkwhichpassesthroughanapertureinoneofthevalves，andfurnishedwithfringedarms，bytheactionofwhichfoodiscarriedtothemouth。BRANCHI&AElig。Gillsororgansforrespirationinwater。BRANCHIALPertainingtogillsorbranchi&aelig……CAMBRIAN

　　SYSTEMASeriesofveryancientPal&aelig。ozoicrocks，betweentheLaurentianandtheSilurian。Untilrecentlythesewereregardedastheoldestfossiliferousrocks。CANID&AElig。TheDog-family，includingtheDog，Wolf，Fox，Jackal，&amp。c。CARAPACETheshellenvelopingtheanteriorpartofthebodyinCrustaceansgenerally。

　　appliedalsotothehardshellypiecesoftheCirripedes。CARBONIFEROUSThistermisappliedtothegreatformationwhichincludes，amongotherrocks，thecoal-measures。Itbelongstotheoldest，orPal&aelig。ozoic，systemofformations。CAUDALOforbelongingtothetail。CEPHALOPODSThehighestclassoftheMollusca，orSoft-bodiedanimals，characterisedbyhavingthemouthsurroundedbyagreaterorlessnumberoffleshyarmsortentacles，which，inmostlivingspecies，arefurnishedwithsucking-cups。

　　Examples，Cuttle-fish，Nautilus。CETACEAAnorderofMammalia，includingtheWhales，Dolphins，&amp。c。，havingtheformofthebodyfish-like，theskinnaked，andonlythefore-limbsdeveloped。CHELONIAAnorderofReptilesincludingtheTurtles，Tortoises，&amp。c。CIRRIPEDESAnorderofCrustaceansincludingtheBarnaclesandAcorn-shells。TheiryoungresemblethoseofmanyotherCrustaceansinform。butwhenmaturetheyarealwaysattachedtootherobjects，eitherdirectlyorbymeansofastalk，andtheirbodiesareenclosedbyacalcareousshellcomposedofseveralpieces，twoofwhichcanopentogiveissuetoabunchofcurled，jointedtentacles，whichrepresentthelimbs。COCCUSThegenusofInsectsincludingtheCochineal。Inthesethemaleisaminute，wingedfly，andthefemalegenerallyamotionless，berry-likemass。COCOONAcaseusuallyofsilkymaterial，inwhichinsectsarefrequentlyenvelopedduringthesecondorresting-stagepupaoftheirexistence。Theterm`cocoon-stage’ishereusedasequivalentto`pupa-stage。’COELOSPERMOUSAtermappliedtothosefruitsoftheUmbellifer&aelig。whichhavetheseedhollowedontheinnerface。COLEOPTERABeetles，anorderofInsects，havingabitingmouthandthefirstpairofwingsmoreorlesshorny，formingsheathsforthesecondpair，andusuallymeetinginastraightlinedownthemiddleoftheback。COLUMNApeculiarorganintheflowersofOrchids，inwhichthestamens，styleandstigmaorthereproductivepartsareunited。COMPOSIT&AElig。

　　orCOMPOSITOUSPLANTSPlantsinwhichtheinflorescenceconsistsofnumeroussmallflowersflorets

　　broughttogetherintoadensehead，thebaseofwhichisenclosedbyacommonenvelope。Examples，theDaisy，Dandelion，&amp。c。CONFERV&AElig。Thefilamentousweedsoffreshwater。CONGLOMERATEArockmadeupoffragmentsofrockorpebbles，cementedtogetherbysomeothermaterial。COROLLAThesecondenvelopeofaflowerusuallycomposedofcoloured，leaf-likeorganspetals，whichmaybeunitedbytheiredgeseitherinthebasalpartorthroughout。CORRELATIONThenormalcoincidenceofonephenomenon，character，&amp。c。，withanother。CORYMBAbunchofflowersinwhichthosespringingfromthelowerpartoftheflowerstalkaresupportedonlongstalkssoastobenearlyonalevelwiththeupperones。COTYLEDONSThefirstorseed-leavesofplants。CRUSTACEANSAclassofarticulatedanimals，havingtheskinofthebodygenerallymoreorlesshardenedbythedepositionofcalcareousmatter，breathingbymeansofgills。Examples，Crab，Lobster，Shrimp，&amp。c。CURCULIOTheoldgenerictermfortheBeetlesknownasWeevils，characterisedbytheirfour-jointedfeet，andbytheheadbeingproducedintoasortofbeak，uponthesidesofwhichtheantenn&aelig。areinserted。CUTANEOUSOforbelongingtotheskin。DEGRADATIONThewearingdownoflandbytheactionoftheseaorofmeteoricagencies。DENUDATIONThewearingawayofthesurfaceofthelandbywater。DEVONIAN

　　SYSTEMorformationAseriesofPal&aelig。ozoicrocks，includingtheOldRedSandstone。DICOTYLEDONS

　　orDICOTYLEDONOUSPLANTSAclassofplantscharacterisedbyhavingtwoseed-leaves，bytheformationofnewwoodbetweenthebarkandtheoldwoodexogenousgrowthandbythereticulationoftheveinsoftheleaves。Thepartsoftheflowersaregenerallyinmultiplesoffive。DIFFERENTIATIONTheseparationordiscriminationofpartsororganswhichinsimplerformsoflifearemoreorlessunited。DIMORPHICHavingtwodistinctforms。Dimorphismistheconditionoftheappearanceofthesamespeciesundertwodissimilarforms。DIOECIOUSHavingtheorgansofthesexesupondistinctindividuals。DIORITEApeculiarformofGreenstone。DORSALOforbelongingtotheback。EDENTATAApeculiarorderofQuadrupeds，characterisedbytheabsenceofatleastthemiddleincisorfrontteethinbothjaws。Examples，theSlothsandArmadillos。ELYTRAThehardenedfore-wingsofBeetles，servingassheathsforthemembranoushind-wings，whichconstitutethetrueorgansofflight。EMBRYOTheyounganimalundergoingdevelopmentwithintheeggorwomb。EMBRYOLOGYThestudyofthedevelopmentoftheembryo。ENDEMICPeculiartoagivenlocality。ENTOMOSTRACAAdivisionoftheclassCrustacea，havingallthesegmentsofthebodyusuallydistinct，gillsattachedtothefeetororgansofthemouth，andthefeetfringedwithfinehairs。Theyaregenerallyofsmallsize。EOCENETheearliestofthethreedivisionsoftheTertiaryepochofgeologists。

　　Rocksofthisagecontainasmallproportionofshellsidenticalwithspeciesnowliving。EPHEMEROUS

　　INSECTSInsectsalliedtotheMay-fly。FAUNAThetotalityoftheanimalsnaturallyinhabitingacertaincountryorregion，orwhichhavelivedduringagivengeologicalperiod。FELID&AElig。TheCat-family。FERALHavingbecomewildfromastateofcultivationordomestication。FLORAThetotalityoftheplantsgrowingnaturallyinacountry，orduringagivengeologicalperiod。FLORETSFlowersimperfectlydevelopedinsomerespects，andcollectedintoadensespikeorhead，asintheGrasses，theDandelion，&amp。c。FOETALOforbelongingtothefoetus，orembryoincourseofdevelopment。FORAMINIFERAAclassofanimalsofveryloworganisation，andgenerallyofsmallsize，havingajelly-likebody，fromtheSurfaceofwhichdelicatefilamentscanbegivenoffandretractedfortheprehensionofexternalobjects，andhavingacalcareousorsandyshell，usuallydividedintochambers，andperforatedwithsmallapertures。FOSSILIFEROUSContainingfossils。FOSSORIALHavingafacultyofdigging。TheFossorialHymenopteraareagroupofWasp-likeInsects，whichburrowinsandysoiltomakenestsfortheiryoung。FRENUM

　　plFRENA。Asmallbandorfoldofskin。FUNGI

　　SingFUNGUS。Aclassofcellularplants，ofwhichMushrooms，Toadstools，andMoulds，arefamiliarexamples。FURCULATheforkedboneformedbytheunionofthecollarbonesinmanybirds，suchasthecommonFowl。GALLINACEOUS

　　BIRDSAnorderofBirdsofwhichthecommonFowl，Turkey，andPheasant，arewell-knownexamples。GALLUSThegenusofbirdswhichincludesthecommonFowl。GANGLIONAswellingorknotfromwhichnervesaregivenoffasfromacentre。GANOID

　　FISHESFishescoveredwithpeculiarenamelledbonyscales。Mostofthemareextinct。GERMINAL

　　VESICLEAminutevesicleintheeggsofanimals，fromwhichdevelopmentoftheembryoproceeds。GLACIAL

　　PERIODAperiodofgreatcoldandofenormousextensionoficeuponthesurfaceoftheearth。Itisbelievedthatglacialperiodshaveoccurredrepeatedlyduringthegeologicalhistoryoftheearth，butthetermisgenerallyappliedtothecloseoftheTertiaryepoch，whennearlythewholeofEuropewassubjectedtoanarcticclimate。GLANDAnorganwhichsecretesorseparatessomepeculiarproductfromthebloodorsapofanimalsorplants。GLOTTISTheopeningofthewindpipeintotheoesophagusorgullet。GNEISSArockapproachinggraniteincomposition，butmoreorlesslaminated，andreallyproducedbythealterationofasedimentarydepositafteritsconsolidation。GRALLATORESTheso-calledWading-birdsStorks，Cranes，Snipes，&amp。c。，whicharegenerallyfurnishedwithlonglegs，bareoffeathersabovetheheel，andhavenomembranesbetweenthetoes。GRANITEArockconsistingessentiallyofcrystaloffelsparandmicainamassofquarts。HABITATThelocalityinwhichaplantoranimalnaturallylives。HEMIPTERAAnorderorsub-orderofInsects，characterisedbythepossessionofajointedbeakorrostrum，andbyhavingthefore-wingshornyinthebasalportionandmembranousattheextremity，wheretheycrosseachother。ThisgroupincludesthevariousspeciesofBugs。HERMAPHRODITEPossessingtheorgansofbothsexes。HOMOLOGYThatrelationbetweenpartswhichresultsfromtheirdevelopmentfromcorrespondingembryonicparts，eitherindifferentanimals，asinthecaseofthearmofman，theforelegofaquadruped，andthewingofabird。orinthesameindividual，asinthecaseoftheforeandhindlegsinquadrupeds，andthesegmentsorringsandtheirappendagesofwhichthebodyofaworm，acentipede，&amp。c。，iscomposed。Thelatteriscalledserialhomology。

　　Thepartswhichstandinsucharelationtoeachotheraresaidtobehomologous，andonesuchpartororganiscalledthehomologueoftheother。

　　Indifferentplantsthepartsoftheflowerarehomologous，andingeneralthesepartsareregardedashomologouswithleaves。HOMOPTERAAnorderorsub-orderofInsectshavingliketheHemipteraajointedbeak，butinwhichthefore-wingsareeitherwhollymembranousorwhollyleathery。TheCicadoe，Frog-hoppers，andAphides，arewell-knownexamples。HYBRIDTheoffspringoftheunionoftwodistinctspecies。HYMENOPTERAAnorderofinsectspossessingbitingjawsandusuallyfourmembranouswingsinwhichthereareafewveins。BeesandWaspsarefamiliarexamplesofthisgroup。HYPERTROPHIEDExcessivelydeveloped。ICHNEUMONID&AElig。AfamilyofHymenopterousinsects，themembersofwhichlaytheireggsinthebodiesoreggsofotherinsects。IMAGOTheperfectgenerallywingedreproductivestateofaninsect。INDIGENSTheaboriginalanimalorvegetableinhabitantsofacountryorregion。INFLORESCENCEThemodeofarrangementoftheflowersofplants。INFUSORIAAclassofmicroscopicAnimalcules，socalledfromtheirhavingoriginallybeenobservedininfusionsofvegetablematters。Theyconsistofagelatinousmaterialenclosedinadelicatemembrane，thewholeorpartofwhichisfurnishedwithshortvibratinghairscalledcilia，bymeansofwhichtheanimalculesswimthroughthewaterorconveytheminuteparticlesoftheirfoodtotheorificeofthemouth。INSECTIVOROUSFeedingonInsects。INVERTEBRATA，orINVERTEBRATEANIMALSThoseanimalswhichdonotpossessabackboneorspinalcolumn。LACUN&AElig。Spacesleftamongthetissuesinsomeoftheloweranimals，andservinginplaceofvesselsforthecirculationofthefluidsofthebody。LAMELLATEDFurnishedwithlamell&aelig。orlittleplates。LARVA

　　plLARV&AElig。。Thefirstconditionofaninsectatitsissuingfromtheegg，whenitisusuallyintheformofagrub，caterpillar，ormaggot。LARYNXTheupperpartofthewindpipeopeningintothegullet。LAURENTIANAgroupofgreatlyalteredandveryancientrocks，whichisgreatlydevelopedalongthecourseoftheSt。Laurence，whencethename。Itisinthesethattheearliestknowntracesoforganicbodieshavebeenfound。LEGUMINOS&AElig。AnorderofplantsrepresentedbythecommonPeasandBeans，havinganirregularflowerinwhichonepetalstandsuplikeawing，andthestamensandpistilareenclosedinasheathformedbytwootherpetals。Thefruitisapodorlegume。LEMURID&AElig。Agroupoffour-handedanimals，distinctfromtheMonkeysandapproachingtheInsectivorousQuadrupedsinsomeoftheircharactersandhabits。Itsmembershavethenostrilscurvedortwisted，andaclawinsteadofanailuponthefirstfingerofthehindhands。LEPIDOPTERAAnorderofInsects，characterisedbythepossessionofaspiralproboscis，andoffourlargemoreorlessscalywings。Itincludesthewell-knownButterfliesandMoths。LITTORALInhabitingtheseashore。LOESSAmarlydepositofrecentPost-Tertiarydate，whichoccupiesagreatpartofthevalleyoftheRhine。MALACOSTRACAThehigherdivisionoftheCrustacea，includingtheordinaryCrabs，Lobsters，Shrimps，&amp。c。，togetherwiththeWoodliceandSand-hoppers。MAMMALIAThehighestclassofanimals，includingtheordinaryhairyquadrupeds，theWhales，andMan，andcharacterisedbytheproductionoflivingyoungwhicharenourishedafterbirthbymilkfromtheteatsMammoe，Mammaryglandsofthemother。Astrikingdifferenceinembryonicdevelopmenthasledtothedivisionofthisclassintotwogreatgroups。inoneofthese，whentheembryohasattainedacertainstage，avascularconnection，calledtheplacenta，isformedbetweentheembryoandthemother。

　　intheotherthisiswanting，andtheyoungareproducedinaveryincompletestate。Theformer，includingthegreaterpartoftheclass，arecalledPlacentalmammals。thelatter，orAplacentalmammals，includetheMarsupialsandMonotremesOrnithorhynchus。MAMMIFEROUSHavingmamm&aelig……orteatsSeeMAMMALIA。MANDIBLES，inInsectsThefirstoruppermostpairofjaws，whicharegenerallysolid，horny，bitingorgans。InBirdsthetermisappliedtobothjawswiththeirhornycoverings。InQuadrupedsthemandibleisproperlythelowerjaw。MARSUPIALSAnorderofMammaliainwhichtheyoungareborninaveryincompletestateofdevelopment，andcarriedbythemother，whilesucking，inaventralpouchmarsupium，suchastheKangaroos，Opossums，&amp。c。seeMAMMALIA。MAXILL&AElig。，inInsectsThesecondorlowerpairofjaws，whicharecomposedofseveraljointsandfurnishedwithpeculiarjointedappendagescalledpalpi，orfeelers。MELANISMTheoppositeofalbinism。anunduedevelopmentofcolouringmaterialintheskinanditsappendages。METAMORPHIC

　　ROCKSSedimentaryrockswhichhaveundergonealteration，generallybytheactionofheat，subsequentlytotheirdepositionandconsolidation。MOLLUSCAOneofthegreatdivisionsoftheAnimalKingdom，includingthoseanimalswhichhaveasoftbody，usuallyfurnishedwithashell，andinwhichthenervousganglia，orcentres，presentnodefinitegeneralarrangement。Theyaregenerallyknownunderthedenominationof`shell-fish。’thecuttle-fish，andthecommonsnails，whelks，oysters，mussels，andcockles，mayserveasexamplesofthem。MONOCOTYLEDONS，orMONOCOTYLEDONOUSPLANTSPlantsinwhichtheseedsendsuponlyasingleseed-leaforcotyledon。

　　characterisedbytheabsenceofconsecutivelayersofwoodinthestemendogenousgrowth，bytheveinsoftheleavesbeinggenerallystraight，andbythepartsoftheflowersbeinggenerallyinmultiplesofthree。

　　Examples，Grasses，Lilies，Orchids，Palms，&amp。c。MORAINESTheaccumulationsoffragmentsofrockbroughtdownbyglaciers。MORPHOLOGYThelawofformorstructureindependentoffunction。MYSIS-STAGEAstageinthedevelopmentofcertainCrustaceansPrawns，inwhichtheycloselyresembletheadultsofagenusMysisbelongingtoaslightlylowergroup。NASCENTCommencingdevelopment。NATATORYAdaptedforthepurposeofswimming。NAUPLIUS-FORMTheearlieststageinthedevelopmentofmanyCrustacea，especiallybelongingtothelowergroups。Inthisstagetheanimalhasashortbody，withindistinctindicationsofadivisionintosegments，andthreepairsoffringedlimbs。

　　Thisformofthecommonfresh-waterCyclopswasdescribedasadistinctgenusunderthenameofNauplius。NEURATIONThearrangementoftheveinsornervuresinthewingsofInsects。NEUTERSImperfectlydevelopedfemalesofcertainsocialinsectssuchasAntsandBees，whichperformallthelaboursofthecommunity。Hencetheyarealsocalledworkers。NICTITATING

　　MEMBRANEAsemi-transparentmembrane，whichcanbedrawnacrosstheeyeinBirdsandReptiles，eithertomoderatetheeffectsofastronglightortosweepparticlesofdust，&amp。c。，fromthesurfaceoftheeye。OCELLIThesimpleeyesorstemmataofInsects，usuallysituatedonthecrownoftheheadbetweenthegreatcompoundeyes。OESOPHAGUSThegullet。OOLITICAgreatseriesofsecondaryrocks，socalledfromthetextureofsomeofitsmembers，whichappeartobemadeupofamassofsmallegg-likecalcareousbodies。OPERCULUMAcalcareousplateemployedbymanyMolluscatoclosetheapertureoftheirshell。TheopercularvalvesofCirripedesarethosewhichclosetheapertureoftheshell。ORBITThebonycavityforthereceptionoftheeye。ORGANISMAnorganisedbeing，whetherplantoranimal。ORTHOSPERMOUSAtermappliedtothosefruitsoftheUmbellifer&aelig。whichhavetheseedstraight。OSCULANTFormsorgroupsapparentlyintermediatebetweenandconnectingothergroupsaresaidtobeosculant。OVAEggs。OVARIUM

　　orOVARYinplantsThelowerpartofthepistilorfemaleorganoftheflower，containingtheovulesorincipientseeds。bygrowthaftertheotherorgansoftheflowerhavefallen，itusuallybecomesconvertedintothefruit。OVIGEROUSEgg-bearing。OVULES

　　ofplantsTheseedsintheearliestcondition。PACHYDERMSAgroupofMammalia，socalledfromtheirthickskins，andincludingtheElephant，Rhinoceros，Hippopotamus，&amp。c。PAL&AElig。OZOICTheoldestsystemoffossiliferousrocks。PALPIJointedappendagestosomeoftheorgansofthemouthinInsectsandCrustacea。PAPILIONACE&AElig。AnorderofPlantsseeLEGUMINOS&AElig。。Theflowersoftheseplantsarecalledpapilionaceous，orbutterfly-like，fromthefanciedresemblanceoftheexpandedsuperiorpetalstothewingsofabutterfly。PARASITEAnanimalorplantlivinguponorin，andattheexpenseof，anotherorganism。PARTHENOGENESISTheproductionoflivingOrganismsfromunimpregnatedeggsorseeds。PEDUNCULATEDSupporteduponastemorstalk。Thepedunculatedoakhasitsacornsborneuponafootstalk。PELORIA

　　orPELORISMTheappearanceofregularityofstructureintheflowersofplantswhichnormallybearirregularflowers。PELVISThebonyarchtowhichthehindlimbsofVertebrateanimalsarearticulated。PETALSTheleavesofthecorolla，orsecondcircleoforgansinaflower。Theyareusuallyofdelicatetextureandbrightlycoloured。PHYLLODINEOUSHavingflattened，leaf-liketwigsorleafstalksinsteadoftrueleaves。PIGMENTThecolouringmaterialproducedgenerallyinthesuperficialpartsofanimals。

　　Thecellssecretingitarecalledpigment-cells。PINNATEBearingleafletsoneachsideofacentralstalk。PISTILSThefemaleorgansofaflower，whichoccupyapositioninthecentreoftheotherfloralorgans。Thepistilisgenerallydivisibleintotheovaryorgermen，thestyleandthestigma。PLACENTALIA，PLACENTATA，orPlacentalMammalsSeeMAMMALIA。PLANTIGRADESQuadrupedswhichwalkuponthewholesoleofthefoot，liketheBears。PLASTICReadilycapableofchange。PLEISTOCENE

　　PERIODThelatestportionoftheTertiaryepoch。PLUMULE

　　inplantsTheminutebudbetweentheseed-leavesofnewly-germinatedplants。PLUTONIC

　　ROCKSRockssupposedtohavebeenproducedbyigneousactioninthedepthsoftheearth。POLLENThemaleelementinfloweringplants。usuallyafinedustproducedbytheanthers，which，bycontactwiththestigmaeffectsthefecundationoftheseeds。Thisimpregnationisbroughtaboutbymeansoftubespollen-tubes

　　whichissuefromthepollen-grainsadheringtothestigma，andpenetratethroughthetissuesuntiltheyreachtheovary。POLYANDROUS

　　flowersFlowershavingmanystamens。POLYGAMOUS

　　PLANTSPlantsinwhichsomeflowersareunisexualandothershermaphrodite。Theunisexualmaleandfemaleflowers，maybeonthesameorondifferentplants。POLYMORPHICPresentingmanyforms。POLYZOARYThecommonstructureforthePolyzoa，suchasthewell-knownSea-mats。PREHENSILECapableofgrasping。PREPOTENTHavingasuperiorityofpower。PRIMARIESThefeathersformingthetipofthewingofabird，andinserteduponthatpartwhichrepresentsthehandofman。PROCESSESProjectingportionsofbones，usuallyfortheattachmentofmuscles，ligaments，&amp。c。PROPOLISAresinousmaterialcollectedbytheHive-Beesfromtheopeningbudsofvarioustrees。PROTEANExceedinglyvariable。PROTOZOAThelowestgreatdivisionoftheAnimalKingdom。Theseanimalsarecomposedofagelatinousmaterial，andshowscarcelyanytraceofdistinctorgans。

　　TheInfusoria，Foraminifera，andSponges，withsomeotherforms，belongtothisdivision。PUPA

　　plPUP&AElig。。ThesecondstageinthedevelopmentofanInsect，fromwhichitemergesintheperfectwingedreproductiveform。Inmostinsectsthepupalstageispassedinperfectrepose。Thechrysalisisthepupalstateofbutterflies。RADICLETheminuterootofanembryoplant。RAMUSOnehalfofthelowerjawintheMammalia。Theportionwhichrisestoarticulatewiththeskulliscalledtheascendingramus。RANGETheextentofcountryoverwhichaplantoranimalisnaturallyspread。Rangeintimeexpressesthedistributionofaspeciesorgroupthroughthefossiliferousbedsoftheearth’scrust。RETINAThedelicateinnercoatoftheeye，formedbynervousfilamentsspreadingfromtheopticnerve，andservingfortheperceptionoftheimpressionsproducedbylight。RETROGRESSIONBackwarddevelopment。Whenananimal，asitapproachesmaturity，becomeslessperfectlyorganisedthanmightbeexpectedfromitsearlystagesandknownrelationships，itissaidtoundergoaretrogradedevelopmentormetamorphosis。RHIZOPODSAclassoflowlyorganisedanimalsprotozoa，havingagelatinousbody，thesurfaceofwhichcanbeprotrudedintheformofroot-likeprocessesorfilaments，whichserveforlocomotionandtheprehensionoffood。ThemostimportantorderisthatoftheForaminifera。RODENTSThegnawingMammalia，suchastheRats，Rabbits，andSquirrels。Theyareespeciallycharacterisedbythepossessionofasinglepairofchisel-likecuttingteethineachjaw，betweenwhichandthegrindingteeththereisagreatgap。RUBUSTheBrambleGenus。RUDIMENTARYVeryimperfectlydeveloped。RUMINANTSThegroupofQuadrupedswhichruminateorchewthecud，suchasoxen，sheep，anddeer。Theyhavedividedhoofs，andaredestituteoffrontteethintheupperjaw。SACRALBelongingtothesacrum，orthebonecomposedusuallyoftwoormoreunitedvertebr&aelig。towhichthesidesofthepelvisinVertebrateanimalsareattached。SARCODEThegelatinousmaterialofwhichthebodiesofthelowestanimalsProtozoa

　　arecomposed。SCUTELL&AElig。Thehornyplateswithwhichthefeetofbirdsaregenerallymoreorlesscovered，especiallyinfront。SEDIMENTARY

　　FORMATIONSRocksdepositedassedimentsfromwater。SEGMENTSThetransverseringsofwhichthebodyofanarticulateanimalorAnnelidiscomposed。SEPALSTheleavesorsegmentsofthecalyx，oroutermostenvelopeofanordinaryflower。Theyareusuallygreen，butsometimesbrightlycoloured。SERRATURESTeethlikethoseofasaw。SESSILENotsupportedonastemorfootstalk。SILURIAN

　　SYSTEMAVeryancientsystemoffossiliferousrocksbelongingtotheearlierpartofthePal&aelig。ozoicseries。SPECIALISATIONThesettingapartofaparticularorganfortheperformanceofaparticularfunction。SPINAL

　　CHORDThecentralportionofthenervoussystemintheVertebrata，whichdescendsfromthebrainthroughthearchesofthevertebr&aelig。，andgivesoffnearlyallthenervestothevariousorgansofthebody。STAMENSThemaleorgansoffloweringplants，standinginacirclewithinthepetals。

　　Theyusuallyconsistofafilamentandananther，theantherbeingtheessentialpartinwhichthepollen，orfecundatingdust，isformed。STERNUMThebreast-bone。STIGMATheapicalportionofthepistilinfloweringplants。STIPULESSmallleafyorgansplacedatthebaseofthefootstalksoftheleavesinmanyplants。STYLEThemiddleportionoftheperfectpistil，whichriseslikeacolumnfromtheovaryandsupportsthestigmaatitssummit。SUBCUTANEOUSSituatedbeneaththeskin。SUCTORIALAdaptedforsucking。SUTURES

　　intheskullThelinesofjunctionofthebonesofwhichtheskulliscomposed。TARSUS

　　plTARSI。Thejointedfeetofarticulateanimals，suchasInsects。TELEOSTEAN

　　FISHESFishesofthekindfamiliartousinthepresentday，havingtheskeletonusuallycompletelyossifiedandthescaleshorny。TENTACULA

　　orTENTACLESDelicatefleshyorgansofprehensionortouchpossessedbymanyoftheloweranimals。TERTIARYThelatestgeologicalepoch，immediatelyprecedingtheestablishmentofthepresentorderofthings。TRACHEAThewindpipeorpassagefortheadmissionofairtothelungs。TRIDACTYLEThree-fingered，orcomposedofthreemovablepartsattachedtoacommonbase。TRILOBITESApeculiargroupofextinctCrustaceans，somewhatresemblingtheWoodliceinexternalform，and，likesomeofthem，capableofrollingthemselvesupintoaball。TheirremainsarefoundonlyinthePal&aelig。ozoicrocks，andmostabundantlyinthoseofSilurianage。TRIMORPHICPresentingthreedistinctforms。UMBELLIFER&AElig。Anorderofplantsinwhichtheflowers，whichcontainfivestamensandapistilwithtwostyles，aresupporteduponfootstalkswhichspringfromthetopoftheflowerstemandspreadoutlikethewiresofanumbrella，soastobringalltheflowersinthesameheadumbelnearlytothesamelevel。Examples，ParsleyandCarrot。UNGULATAHoofedquadrupeds。UNICELLULARConsistingofasinglecell。VASCULARContainingblood-vesselsVERMIFORMLikeaworm。VERTEBRATA：

　　orVERTEBRATEANIMALSThehighestdivisionoftheanimalkingdom，socalledfromthepresenceinmostcasesofabackbonecomposedofnumerousjointsorvertebroe，whichconstitutesthecentreoftheskeletonandatthesametimesupportsandprotectsthecentralpartsofthenervoussystem。WHORLSThecirclesorspirallinesinwhichthepartsofplantsarearrangedupontheaxisofgrowth。WORKERSSeeneuters。ZOEA-STAGETheearlieststageinthedevelopmentofmanyofthehigherCrustacea，socalledfromthenameofZoeaappliedtotheseyounganimalswhentheyweresupposedtoconstituteapeculiargenus。ZOOIDSInmanyoftheloweranimalssuchastheCorals，Medus&aelig。，&amp。c。

　　reproductiontakesplaceintwoways，namely，bymeansofeggsandbyaprocessofbuddingwithorwithoutseparationfromtheparentoftheproductofthelatter，whichisoftenverydifferentfromthatoftheegg。Theindividualityofthespeciesisrepresentedbythewholeoftheformproducedbetweentwosexualreproductions。andtheseforms，whichareapparentlyindividualanimals，havebeencalledzooids。