第12章

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，&。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，’&。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。Systematistswillhaveonlytodecide(notthatthiswillbeeasy)whetheranyformbesufficientlyconstantanddistinctfromotherforms，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，&。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

(inOptics)Intherefractionoflightbyaconvexlenstherayspassingthroughdifferentpartsofthelensarebroughttoafocusatslightlydifferentdistances，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。ANTENNÆ。JointedorgansappendedtotheheadinInsects，CrustaceaandCentipedes，andnotbelongingtothemouth。ANTHERSThesummitsofthestamensofflowers，inwhichthepollenorfertilisingdustisproduced。APLACENTALIA，APLACENTATAorAplacentalMammalsSeeMammalia。ARCHETYPALOforbelongingtotheArchetype，oridealprimitiveformuponwhichallthebeingsofagroupseemtobeorganised。ARTICULATAAgreatdivisionoftheAnimalKingdomcharacterisedgenerallybyhavingthesurfaceofthebodydividedintoringscalledsegments，agreaterorlessnumberofwhicharefurnishedwithjointedlegs(suchasInsects，CrustaceansandCentipedes)。ASYMMETRICALHavingthetwosidesunlike。ATROPHIEDArrestedindevelopmentataveryearlystage。BALANUSThegenusincludingthecommonAcorn-shellswhichliveinabundanceontherocksofthesea-coast。BATRACHIANSAclassofanimalsalliedtotheReptiles，butundergoingapeculiarmetamorphosis，inwhichtheyounganimalisgenerallyaquaticandbreathesbygills。(Examples，Frogs，Toads，andNewts。)BOULDERSLargetransportedblocksofstonegenerallyimbeddedinclaysorgravels。BRACHIOPODAAclassofmarineMollusca，orsoft-bodiedanimals，furnishedwithabivalveshell，attachedtosubmarineobjectsbyastalkwhichpassesthroughanapertureinoneofthevalves，andfurnishedwithfringedarms，bytheactionofwhichfoodiscarriedtothemouth。BRANCHIÆ。Gillsororgansforrespirationinwater。BRANCHIALPertainingtogillsorbranchiæ……CAMBRIAN

SYSTEMASeriesofveryancientPalæ。ozoicrocks，betweentheLaurentianandtheSilurian。Untilrecentlythesewereregardedastheoldestfossiliferousrocks。CANIDÆ。TheDog-family，includingtheDog，Wolf，Fox，Jackal，&。c。CARAPACETheshellenvelopingtheanteriorpartofthebodyinCrustaceansgenerally。

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

(Examples，Cuttle-fish，Nautilus。)CETACEAAnorderofMammalia，includingtheWhales，Dolphins，&。c。，havingtheformofthebodyfish-like，theskinnaked，andonlythefore-limbsdeveloped。CHELONIAAnorderofReptilesincludingtheTurtles，Tortoises，&。c。CIRRIPEDESAnorderofCrustaceansincludingtheBarnaclesandAcorn-shells。TheiryoungresemblethoseofmanyotherCrustaceansinform。butwhenmaturetheyarealwaysattachedtootherobjects，eitherdirectlyorbymeansofastalk，andtheirbodiesareenclosedbyacalcareousshellcomposedofseveralpieces，twoofwhichcanopentogiveissuetoabunchofcurled，jointedtentacles，whichrepresentthelimbs。COCCUSThegenusofInsectsincludingtheCochineal。Inthesethemaleisaminute，wingedfly，andthefemalegenerallyamotionless，berry-likemass。COCOONAcaseusuallyofsilkymaterial，inwhichinsectsarefrequentlyenvelopedduringthesecondorresting-stage(pupa)oftheirexistence。Theterm`cocoon-stage’ishereusedasequivalentto`pupa-stage。’COELOSPERMOUSAtermappliedtothosefruitsoftheUmbelliferæ。whichhavetheseedhollowedontheinnerface。COLEOPTERABeetles，anorderofInsects，havingabitingmouthandthefirstpairofwingsmoreorlesshorny，formingsheathsforthesecondpair，andusuallymeetinginastraightlinedownthemiddleoftheback。COLUMNApeculiarorganintheflowersofOrchids，inwhichthestamens，styleandstigma(orthereproductiveparts)areunited。COMPOSITÆ。

orCOMPOSITOUSPLANTSPlantsinwhichtheinflorescenceconsistsofnumeroussmallflowers(florets)

broughttogetherintoadensehead，thebaseofwhichisenclosedbyacommonenvelope。(Examples，theDaisy，Dandelion，&。c。)CONFERVÆ。Thefilamentousweedsoffreshwater。CONGLOMERATEArockmadeupoffragmentsofrockorpebbles，cementedtogetherbysomeothermaterial。COROLLAThesecondenvelopeofaflowerusuallycomposedofcoloured，leaf-likeorgans(petals)，whichmaybeunitedbytheiredgeseitherinthebasalpartorthroughout。CORRELATIONThenormalcoincidenceofonephenomenon，character，&。c。，withanother。CORYMBAbunchofflowersinwhichthosespringingfromthelowerpartoftheflowerstalkaresupportedonlongstalkssoastobenearlyonalevelwiththeupperones。COTYLEDONSThefirstorseed-leavesofplants。CRUSTACEANSAclassofarticulatedanimals，havingtheskinofthebodygenerallymoreorlesshardenedbythedepositionofcalcareousmatter，breathingbymeansofgills。(Examples，Crab，Lobster，Shrimp，&。c。)CURCULIOTheoldgenerictermfortheBeetlesknownasWeevils，characterisedbytheirfour-jointedfeet，andbytheheadbeingproducedintoasortofbeak，uponthesidesofwhichtheantennæ。areinserted。CUTANEOUSOforbelongingtotheskin。DEGRADATIONThewearingdownoflandbytheactionoftheseaorofmeteoricagencies。DENUDATIONThewearingawayofthesurfaceofthelandbywater。DEVONIAN

SYSTEMorformationAseriesofPalæ。ozoicrocks，includingtheOldRedSandstone。DICOTYLEDONS

orDICOTYLEDONOUSPLANTSAclassofplantscharacterisedbyhavingtwoseed-leaves，bytheformationofnewwoodbetweenthebarkandtheoldwood(exogenousgrowth)andbythereticulationoftheveinsoftheleaves。Thepartsoftheflowersaregenerallyinmultiplesoffive。DIFFERENTIATIONTheseparationordiscriminationofpartsororganswhichinsimplerformsoflifearemoreorlessunited。DIMORPHICHavingtwodistinctforms。Dimorphismistheconditionoftheappearanceofthesamespeciesundertwodissimilarforms。DIOECIOUSHavingtheorgansofthesexesupondistinctindividuals。DIORITEApeculiarformofGreenstone。DORSALOforbelongingtotheback。EDENTATAApeculiarorderofQuadrupeds，characterisedbytheabsenceofatleastthemiddleincisor(front)teethinbothjaws。(Examples，theSlothsandArmadillos。)ELYTRAThehardenedfore-wingsofBeetles，servingassheathsforthemembranoushind-wings，whichconstitutethetrueorgansofflight。EMBRYOTheyounganimalundergoingdevelopmentwithintheeggorwomb。EMBRYOLOGYThestudyofthedevelopmentoftheembryo。ENDEMICPeculiartoagivenlocality。ENTOMOSTRACAAdivisionoftheclassCrustacea，havingallthesegmentsofthebodyusuallydistinct，gillsattachedtothefeetororgansofthemouth，andthefeetfringedwithfinehairs。Theyaregenerallyofsmallsize。EOCENETheearliestofthethreedivisionsoftheTertiaryepochofgeologists。

Rocksofthisagecontainasmallproportionofshellsidenticalwithspeciesnowliving。EPHEMEROUS

INSECTSInsectsalliedtotheMay-fly。FAUNAThetotalityoftheanimalsnaturallyinhabitingacertaincountryorregion，orwhichhavelivedduringagivengeologicalperiod。FELIDÆ。TheCat-family。FERALHavingbecomewildfromastateofcultivationordomestication。FLORAThetotalityoftheplantsgrowingnaturallyinacountry，orduringagivengeologicalperiod。FLORETSFlowersimperfectlydevelopedinsomerespects，andcollectedintoadensespikeorhead，asintheGrasses，theDandelion，&。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-birds(Storks，Cranes，Snipes，&。c。)，whicharegenerallyfurnishedwithlonglegs，bareoffeathersabovetheheel，andhavenomembranesbetweenthetoes。GRANITEArockconsistingessentiallyofcrystaloffelsparandmicainamassofquarts。HABITATThelocalityinwhichaplantoranimalnaturallylives。HEMIPTERAAnorderorsub-orderofInsects，characterisedbythepossessionofajointedbeakorrostrum，andbyhavingthefore-wingshornyinthebasalportionandmembranousattheextremity，wheretheycrosseachother。ThisgroupincludesthevariousspeciesofBugs。HERMAPHRODITEPossessingtheorgansofbothsexes。HOMOLOGYThatrelationbetweenpartswhichresultsfromtheirdevelopmentfromcorrespondingembryonicparts，eitherindifferentanimals，asinthecaseofthearmofman，theforelegofaquadruped，andthewingofabird。orinthesameindividual，asinthecaseoftheforeandhindlegsinquadrupeds，andthesegmentsorringsandtheirappendagesofwhichthebodyofaworm，acentipede，&。c。，iscomposed。Thelatteriscalledserialhomology。

Thepartswhichstandinsucharelationtoeachotheraresaidtobehomologous，andonesuchpartororganiscalledthehomologueoftheother。

Indifferentplantsthepartsoftheflowerarehomologous，andingeneralthesepartsareregardedashomologouswithleaves。HOMOPTERAAnorderorsub-orderofInsectshaving(liketheHemiptera)ajointedbeak，butinwhichthefore-wingsareeitherwhollymembranousorwhollyleathery。TheCicadoe，Frog-hoppers，andAphides，arewell-knownexamples。HYBRIDTheoffspringoftheunionoftwodistinctspecies。HYMENOPTERAAnorderofinsectspossessingbitingjawsandusuallyfourmembranouswingsinwhichthereareafewveins。BeesandWaspsarefamiliarexamplesofthisgroup。HYPERTROPHIEDExcessivelydeveloped。ICHNEUMONIDÆ。AfamilyofHymenopterousinsects，themembersofwhichlaytheireggsinthebodiesoreggsofotherinsects。IMAGOTheperfect(generallywinged)reproductivestateofaninsect。INDIGENSTheaboriginalanimalorvegetableinhabitantsofacountryorregion。INFLORESCENCEThemodeofarrangementoftheflowersofplants。INFUSORIAAclassofmicroscopicAnimalcules，socalledfromtheirhavingoriginallybeenobservedininfusionsofvegetablematters。Theyconsistofagelatinousmaterialenclosedinadelicatemembrane，thewholeorpartofwhichisfurnishedwithshortvibratinghairs(calledcilia)，bymeansofwhichtheanimalculesswimthroughthewaterorconveytheminuteparticlesoftheirfoodtotheorificeofthemouth。INSECTIVOROUSFeedingonInsects。INVERTEBRATA，orINVERTEBRATEANIMALSThoseanimalswhichdonotpossessabackboneorspinalcolumn。LACUNÆ。Spacesleftamongthetissuesinsomeoftheloweranimals，andservinginplaceofvesselsforthecirculationofthefluidsofthebody。LAMELLATEDFurnishedwithlamellæ。orlittleplates。LARVA

(plLARVÆ。)。Thefirstconditionofaninsectatitsissuingfromtheegg，whenitisusuallyintheformofagrub，caterpillar，ormaggot。LARYNXTheupperpartofthewindpipeopeningintothegullet。LAURENTIANAgroupofgreatlyalteredandveryancientrocks，whichisgreatlydevelopedalongthecourseoftheSt。Laurence，whencethename。Itisinthesethattheearliestknowntracesoforganicbodieshavebeenfound。LEGUMINOSÆ。AnorderofplantsrepresentedbythecommonPeasandBeans，havinganirregularflowerinwhichonepetalstandsuplikeawing，andthestamensandpistilareenclosedinasheathformedbytwootherpetals。Thefruitisapod(orlegume)。LEMURIDÆ。Agroupoffour-handedanimals，distinctfromtheMonkeysandapproachingtheInsectivorousQuadrupedsinsomeoftheircharactersandhabits。Itsmembershavethenostrilscurvedortwisted，andaclawinsteadofanailuponthefirstfingerofthehindhands。LEPIDOPTERAAnorderofInsects，characterisedbythepossessionofaspiralproboscis，andoffourlargemoreorlessscalywings。Itincludesthewell-knownButterfliesandMoths。LITTORALInhabitingtheseashore。LOESSAmarlydepositofrecent(Post-Tertiary)date，whichoccupiesagreatpartofthevalleyoftheRhine。MALACOSTRACAThehigherdivisionoftheCrustacea，includingtheordinaryCrabs，Lobsters，Shrimps，&。c。，togetherwiththeWoodliceandSand-hoppers。MAMMALIAThehighestclassofanimals，includingtheordinaryhairyquadrupeds，theWhales，andMan，andcharacterisedbytheproductionoflivingyoungwhicharenourishedafterbirthbymilkfromtheteats(Mammoe，Mammaryglands)ofthemother。Astrikingdifferenceinembryonicdevelopmenthasledtothedivisionofthisclassintotwogreatgroups。inoneofthese，whentheembryohasattainedacertainstage，avascularconnection，calledtheplacenta，isformedbetweentheembryoandthemother。

intheotherthisiswanting，andtheyoungareproducedinaveryincompletestate。Theformer，includingthegreaterpartoftheclass，arecalledPlacentalmammals。thelatter，orAplacentalmammals，includetheMarsupialsandMonotremes(Ornithorhynchus)。MAMMIFEROUSHavingmammæ……orteats(SeeMAMMALIA)。MANDIBLES，inInsectsThefirstoruppermostpairofjaws，whicharegenerallysolid，horny，bitingorgans。InBirdsthetermisappliedtobothjawswiththeirhornycoverings。InQuadrupedsthemandibleisproperlythelowerjaw。MARSUPIALSAnorderofMammaliainwhichtheyoungareborninaveryincompletestateofdevelopment，andcarriedbythemother，whilesucking，inaventralpouch(marsupium)，suchastheKangaroos，Opossums，&。c。(seeMAMMALIA)。MAXILLÆ。，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-leaf(orcotyledon)。

characterisedbytheabsenceofconsecutivelayersofwoodinthestem(endogenousgrowth)，bytheveinsoftheleavesbeinggenerallystraight，andbythepartsoftheflowersbeinggenerallyinmultiplesofthree。

(Examples，Grasses，Lilies，Orchids，Palms，&。c。)MORAINESTheaccumulationsoffragmentsofrockbroughtdownbyglaciers。MORPHOLOGYThelawofformorstructureindependentoffunction。MYSIS-STAGEAstageinthedevelopmentofcertainCrustaceans(Prawns)，inwhichtheycloselyresembletheadultsofagenus(Mysis)belongingtoaslightlylowergroup。NASCENTCommencingdevelopment。NATATORYAdaptedforthepurposeofswimming。NAUPLIUS-FORMTheearlieststageinthedevelopmentofmanyCrustacea，especiallybelongingtothelowergroups。Inthisstagetheanimalhasashortbody，withindistinctindicationsofadivisionintosegments，andthreepairsoffringedlimbs。

Thisformofthecommonfresh-waterCyclopswasdescribedasadistinctgenusunderthenameofNauplius。NEURATIONThearrangementoftheveinsornervuresinthewingsofInsects。NEUTERSImperfectlydevelopedfemalesofcertainsocialinsects(suchasAntsandBees)，whichperformallthelaboursofthecommunity。Hencetheyarealsocalledworkers。NICTITATING

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

orOVARY(inplants)Thelowerpartofthepistilorfemaleorganoftheflower，containingtheovulesorincipientseeds。bygrowthaftertheotherorgansoftheflowerhavefallen，itusuallybecomesconvertedintothefruit。OVIGEROUSEgg-bearing。OVULES

(ofplants)Theseedsintheearliestcondition。PACHYDERMSAgroupofMammalia，socalledfromtheirthickskins，andincludingtheElephant，Rhinoceros，Hippopotamus，&。c。PALÆ。OZOICTheoldestsystemoffossiliferousrocks。PALPIJointedappendagestosomeoftheorgansofthemouthinInsectsandCrustacea。PAPILIONACEÆ。AnorderofPlants(seeLEGUMINOSÆ。)。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

(inplants)Theminutebudbetweentheseed-leavesofnewly-germinatedplants。PLUTONIC

ROCKSRockssupposedtohavebeenproducedbyigneousactioninthedepthsoftheearth。POLLENThemaleelementinfloweringplants。usuallyafinedustproducedbytheanthers，which，bycontactwiththestigmaeffectsthefecundationoftheseeds。Thisimpregnationisbroughtaboutbymeansoftubes(pollen-tubes)

whichissuefromthepollen-grainsadheringtothestigma，andpenetratethroughthetissuesuntiltheyreachtheovary。POLYANDROUS

(flowers)Flowershavingmanystamens。POLYGAMOUS

PLANTSPlantsinwhichsomeflowersareunisexualandothershermaphrodite。Theunisexual(maleandfemale)flowers，maybeonthesameorondifferentplants。POLYMORPHICPresentingmanyforms。POLYZOARYThecommonstructureforthePolyzoa，suchasthewell-knownSea-mats。PREHENSILECapableofgrasping。PREPOTENTHavingasuperiorityofpower。PRIMARIESThefeathersformingthetipofthewingofabird，andinserteduponthatpartwhichrepresentsthehandofman。PROCESSESProjectingportionsofbones，usuallyfortheattachmentofmuscles，ligaments，&。c。PROPOLISAresinousmaterialcollectedbytheHive-Beesfromtheopeningbudsofvarioustrees。PROTEANExceedinglyvariable。PROTOZOAThelowestgreatdivisionoftheAnimalKingdom。Theseanimalsarecomposedofagelatinousmaterial，andshowscarcelyanytraceofdistinctorgans。

TheInfusoria，Foraminifera，andSponges，withsomeotherforms，belongtothisdivision。PUPA

(plPUPÆ。)。ThesecondstageinthedevelopmentofanInsect，fromwhichitemergesintheperfect(winged)reproductiveform。Inmostinsectsthepupalstageispassedinperfectrepose。Thechrysalisisthepupalstateofbutterflies。RADICLETheminuterootofanembryoplant。RAMUSOnehalfofthelowerjawintheMammalia。Theportionwhichrisestoarticulatewiththeskulliscalledtheascendingramus。RANGETheextentofcountryoverwhichaplantoranimalisnaturallyspread。Rangeintimeexpressesthedistributionofaspeciesorgroupthroughthefossiliferousbedsoftheearth’scrust。RETINAThedelicateinnercoatoftheeye，formedbynervousfilamentsspreadingfromtheopticnerve，andservingfortheperceptionoftheimpressionsproducedbylight。RETROGRESSIONBackwarddevelopment。Whenananimal，asitapproachesmaturity，becomeslessperfectlyorganisedthanmightbeexpectedfromitsearlystagesandknownrelationships，itissaidtoundergoaretrogradedevelopmentormetamorphosis。RHIZOPODSAclassoflowlyorganisedanimals(protozoa)，havingagelatinousbody，thesurfaceofwhichcanbeprotrudedintheformofroot-likeprocessesorfilaments，whichserveforlocomotionandtheprehensionoffood。ThemostimportantorderisthatoftheForaminifera。RODENTSThegnawingMammalia，suchastheRats，Rabbits，andSquirrels。Theyareespeciallycharacterisedbythepossessionofasinglepairofchisel-likecuttingteethineachjaw，betweenwhichandthegrindingteeththereisagreatgap。RUBUSTheBrambleGenus。RUDIMENTARYVeryimperfectlydeveloped。RUMINANTSThegroupofQuadrupedswhichruminateorchewthecud，suchasoxen，sheep，anddeer。Theyhavedividedhoofs，andaredestituteoffrontteethintheupperjaw。SACRALBelongingtothesacrum，orthebonecomposedusuallyoftwoormoreunitedvertebræ。towhichthesidesofthepelvisinVertebrateanimalsareattached。SARCODEThegelatinousmaterialofwhichthebodiesofthelowestanimals(Protozoa)

arecomposed。SCUTELLÆ。Thehornyplateswithwhichthefeetofbirdsaregenerallymoreorlesscovered，especiallyinfront。SEDIMENTARY

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

SYSTEMAVeryancientsystemoffossiliferousrocksbelongingtotheearlierpartofthePalæ。ozoicseries。SPECIALISATIONThesettingapartofaparticularorganfortheperformanceofaparticularfunction。SPINAL

CHORDThecentralportionofthenervoussystemintheVertebrata，whichdescendsfromthebrainthroughthearchesofthevertebræ。，andgivesoffnearlyallthenervestothevariousorgansofthebody。STAMENSThemaleorgansoffloweringplants，standinginacirclewithinthepetals。

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

(intheskull)Thelinesofjunctionofthebonesofwhichtheskulliscomposed。TARSUS

(plTARSI)。Thejointedfeetofarticulateanimals，suchasInsects。TELEOSTEAN

FISHESFishesofthekindfamiliartousinthepresentday，havingtheskeletonusuallycompletelyossifiedandthescaleshorny。TENTACULA

orTENTACLESDelicatefleshyorgansofprehensionortouchpossessedbymanyoftheloweranimals。TERTIARYThelatestgeologicalepoch，immediatelyprecedingtheestablishmentofthepresentorderofthings。TRACHEAThewindpipeorpassagefortheadmissionofairtothelungs。TRIDACTYLEThree-fingered，orcomposedofthreemovablepartsattachedtoacommonbase。TRILOBITESApeculiargroupofextinctCrustaceans，somewhatresemblingtheWoodliceinexternalform，and，likesomeofthem，capableofrollingthemselvesupintoaball。TheirremainsarefoundonlyinthePalæ。ozoicrocks，andmostabundantlyinthoseofSilurianage。TRIMORPHICPresentingthreedistinctforms。UMBELLIFERÆ。Anorderofplantsinwhichtheflowers，whichcontainfivestamensandapistilwithtwostyles，aresupporteduponfootstalkswhichspringfromthetopoftheflowerstemandspreadoutlikethewiresofanumbrella，soastobringalltheflowersinthesamehead(umbel)nearlytothesamelevel。(Examples，ParsleyandCarrot)。UNGULATAHoofedquadrupeds。UNICELLULARConsistingofasinglecell。VASCULARContainingblood-vesselsVERMIFORMLikeaworm。VERTEBRATA：

orVERTEBRATEANIMALSThehighestdivisionoftheanimalkingdom，socalledfromthepresenceinmostcasesofabackbonecomposedofnumerousjointsorvertebroe，whichconstitutesthecentreoftheskeletonandatthesametimesupportsandprotectsthecentralpartsofthenervoussystem。WHORLSThecirclesorspirallinesinwhichthepartsofplantsarearrangedupontheaxisofgrowth。WORKERSSeeneuters。ZOEA-STAGETheearlieststageinthedevelopmentofmanyofthehigherCrustacea，socalledfromthenameofZoeaappliedtotheseyounganimalswhentheyweresupposedtoconstituteapeculiargenus。ZOOIDSInmanyoftheloweranimals(suchastheCorals，Medusæ。，&。c。)

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