IntheexperimentsonthehybridHippeastrums，ifHerberthadfoundthatthepollenoftwoorthreekindsalonehadbeenmoreefficientoncertainkindsthantheirownpollen，itmighthavebeenarguedthatthese，fromtheirmixedparentage，hadaclosermutualaffinitythantheothers;butthisexplanationisinadmissible，forthetrialsweremadereciprocallybackwardsandforwardsonninedifferenthybrids;andacross，whicheverwaytaken，alwaysprovedhighlybeneficial。IcanaddastrikingandanalogouscasefromexperimentsmadebytheRev。A。Rawson，ofBromleyCommon，withsomecomplexhybridsofGladiolus。ThisskilfulhorticulturistpossessedanumberofFrenchvarieties，differingfromeachotheronlyinthecolourandsizeoftheflowers，alldescendedfromGandavensis，awell—knownoldhybrid，saidtobedescendedfromG。natalensisbythepollenofG。oppositiflorus。（17/86。Mr。D。Beatonin’JournalofHort。’1861page453。Lecoqhowever（’DelaFecond。’1862page369）statesthatthishybridisdescendedfromG。psittacinusandcardinalis;
　　butthisisopposedtoHerbert’sexperience，whofoundthattheformerspeciescouldnotbecrossed。）Mr。Rawson，afterrepeatedtrials，foundthatnoneofthevarietieswouldsetseedwiththeirownpollen，althoughtakenfromdistinctplantsofthesamevariety（whichhad，ofcourse，beenpropagatedbybulbs），butthattheyallseededfreelywithpollenfromanyothervariety。Togivetwoexamples:Ophirdidnotproduceacapsulewithitsownpollen，butwhenfertilisedwiththatofJanire，Brenchleyensis，VulcainandLinne，itproducedtenfinecapsules;butthepollenofOphirwasgood，forwhenLinnewasfertilisedbyitsevencapsuleswereproduced。Thislattervariety，ontheotherhand，wasutterlybarrenwithitsownpollen，whichwehaveseenwasperfectlyefficientonOphir。Altogether，Mr。Rawson，intheyear1861
　　fertilisedtwenty—sixflowersbornebyfourvarietieswithpollentakenfromothervarieties，andeverysingleflowerproducedafineseed—capsule;whereasfifty—twoflowersonthesameplants，fertilisedatthesametimewiththeirownpollen，didnotyieldasingleseed—capsule。Mr。Rawsonfertilised，insomecases，thealternateflowers，andinothercasesallthosedownonesideofthespike，withpollenofothervarieties，andtheremainingflowerswiththeirownpollen。Isawtheseplantswhenthecapsuleswerenearlymature，andtheircuriousarrangementatoncebroughtfullconvictiontothemindthatanimmenseadvantagehadbeenderivedfromcrossingthesehybrids。
　　Lastly，IhaveheardfromDr。E。Bornet，ofAntibes，whohasmadenumerousexperimentsincrossingthespeciesofCistus，buthasnotyetpublishedtheresults，that，whenanyofthesehybridsarefertile，theymaybesaidtobe，inregardtofunction，dioecious;"fortheflowersarealwayssterilewhenthepistilisfertilisedbypollentakenfromthesameflowerorfromflowersonthesameplant。Buttheyareoftenfertileifpollenbeemployedfromadistinctindividualofthesamehybridnature，orfromahybridmadebyareciprocalcross。"]
　　CONCLUSION。
　　Thatplantsshouldbeself—sterile，althoughbothsexualelementsareinafitstateforreproduction，appearsatfirstsightopposedtoallanalogy。Withrespecttothespecies，alltheindividualsofwhichareinthisstate，althoughlivingundertheirnaturalconditions，wemayconcludethattheirself—sterilityhasbeenacquiredforthesakeofeffectuallypreventingself—
　　fertilisation。Thecaseiscloselyanalogouswiththatofdimorphicandtrimorphicorheterostyledplants，whichcanbefullyfertilisedonlybyplantsbelongingtoadifferentform，andnot，asintheforegoingcases，indifferentlybyanyotherindividualofthespecies。Someofthesehetero—
　　styledplantsarecompletelysterilewithpollentakenfromthesameplantorfromthesameform。Withrespecttospecieslivingundertheirnaturalconditions，ofwhichonlycertainindividualsareself—sterile（aswithResedalutea），itisprobablethatthesehavebeenrenderedself—steriletoensureoccasionalcross—fertilisation，whilstotherindividualshaveremainedself—
　　fertiletoensurethepropagationofthespecies。Thecaseseemstobeparallelwiththatofplantswhichproduce，asHermannMullerhasdiscovered，twoforms——onebearingmoreconspicuousflowerswiththeirstructureadaptedforcross—fertilisationbyinsects，andtheotherformwithlessconspicuousflowersadaptedforself—fertilisation。Theself—sterility，however，ofsomeoftheforegoingplantsisincidentalontheconditionstowhichtheyhavebeensubjected，aswiththeEschscholtzia，theVerbascumphoeniceum（thesterilityofwhichvariedaccordingtotheseason），andwiththePassifloraalata，whichrecovereditsself—fertilitywhengraftedonadifferentstock。
　　Itisinterestingtoobserveintheaboveseveralcasesthegraduatedseriesfromplantswhich，whenfertilisedbytheirownpollen，yieldthefullnumberofseeds，butwiththeseedlingsalittledwarfedinstature——toplantswhichwhenself—fertilisedyieldfewseeds——tothosewhichyieldnone，buthavetheirovariasomewhatdeveloped——and，lastly，tothoseinwhichtheplant’sownpollenandstigmamutuallyactononeanotherlikepoison。Itisalsointerestingtoobserveonhowslightadifferenceinthenatureofthepollenoroftheovulescompleteself—sterilityorcompleteself—fertilitymustdependinsomeoftheabovecases。Everyindividualoftheself—sterilespeciesappearstobecapableofproducingthefullcomplementofseedwhenfertilisedbythepollenofanyotherindividual（thoughjudgingfromthefactsgivenwithrespecttoAbutilonthenearestkinmustbeexcepted）;butnotoneindividualcanbefertilisedbyitsownpollen。Aseveryorganismdiffersinsomeslightdegreefromeveryotherindividualofthesamespecies，sonodoubtitiswiththeirpollenandovules;andintheabovecaseswemustbelievethatcompleteself—sterilityandcompleteself—fertilitydependonsuchslightdifferencesintheovulesandpollen，andnottheirhavingbeendifferentiatedinsomespecialmannerinrelationtooneanother;foritisimpossiblethatthesexualelementsofmanythousandindividualsshouldhavebeenspecialisedinrelationtoeveryotherindividual。Insome，however，oftheabovecases，aswithcertainPassifloras，anamountofdifferentiationbetweenthepollenandovulessufficientforfertilisationisgainedonlybyemployingpollenfromadistinctspecies;butthisisprobablytheresultofsuchplantshavingbeenrenderedsomewhatsterilefromtheunnaturalconditionstowhichtheyhavebeenexposed。
　　Exoticanimalsconfinedinmenageriesaresometimesinnearlythesamestateastheabove—describedself—impotentplants;for，asweshallseeinthefollowingchapter，certainmonkeys，thelargercarnivora，severalfinches，geese，andpheasants，crosstogether，quiteasfreelyas，orevenmorefreelythantheindividualsofthesamespeciesbreedtogether。Caseswill，also，begivenofsexualincompatibilitybetweencertain，maleandfemaledomesticatedanimals，which，nevertheless，arefertilewhenmatchedwithanyotherindividualofthesamekind。
　　Intheearlypartofthischapteritwasshownthatthecrossingofindividualsbelongingtodistinctfamiliesofthesamerace，ortodifferentracesorspecies，givesincreasedsizeandconstitutionalvigourtotheoffspring，and，exceptinthecaseofcrossedspecies，increasedfertility。
　　Theevidencerestsontheuniversaltestimonyofbreeders（foritshouldbeobservedthatIamnotherespeakingoftheevilresultsofcloseinterbreeding），andispracticallyexemplifiedinthehighervalueofcross—
　　bredanimalsforimmediateconsumption。Thegoodresultsofcrossinghavealsobeendemonstratedwithsomeanimalsandwithnumerousplants，byactualweightandmeasurement。Althoughanimalsofpurebloodwillobviouslybedeterioratedbycrossing，asfarastheircharacteristicqualitiesareconcerned，thereseemstobenoexceptiontotherulethatadvantagesofthekindjustmentionedarethusgained，evenwhentherehasnotbeenanypreviouscloseinterbreeding;andtheruleappliestosuchanimalsascattleandsheep，whichcanlongresistbreedingin—and—inbetweenthenearestblood—relations。
　　Inthecaseofcrossedspecies，althoughsize，vigour，precocity，andhardinessare，withrareexceptions，gained，fertility，inagreaterorlessdegree，islost;butthegainintheaboverespectscanhardlybeattributedtotheprincipleofcompensation;forthereisnocloseparallelismbetweentheincreasedsizeandvigourofhybridoffspringandtheirsterility。
　　Moreover，ithasbeenclearlyprovedthatmongrelswhichareperfectlyfertilegainthesesameadvantagesaswellassterilehybrids。
　　Withthehigheranimalsnospecialadaptationsforensuringoccasionalcrossesbetweendistinctfamiliesseemtoexist。Theeagernessofthemales，leadingtoseverecompetitionbetweenthem，issufficient;forevenwithgregariousanimals，theoldanddominantmaleswillbedispossessedafteratimeanditwouldbeamerechanceifacloselyrelatedmemberofthesamefamilyweretobethevictorioussuccessor。Thestructureofmanyoftheloweranimals，whentheyarehermaphrodites，issuchastopreventtheovulesbeingfertilisedbythemaleelementofthesameindividual;sothattheconcourseoftwoindividualsisnecessary。Inothercasestheaccessofthemaleelementofadistinctindividualisatleastpossible。Withplants，whichareaffixedtothegroundandcannotwanderfromplacetoplacelikeanimals，thenumerousadaptationsforcross—fertilisationarewonderfullyperfect，ashasbeenadmittedbyeveryonewhohasstudiedthesubject。
　　Theevilconsequencesoflong—continuedcloseinterbreedingarenotsoeasilyrecognisedasthegoodeffectsfromcrossing，forthedeteriorationisgradual。Nevertheless，itisthegeneralopinionofthosewhohavehadmostexperience，especiallywithanimalswhichpropagatequickly，thatevildoesinevitablyfollowsoonerorlater，butatdifferentrateswithdifferentanimals。Nodoubtafalsebeliefmay，likeasuperstition，prevailwidely;yetitisdifficulttosupposethatsomanyacuteobservershaveallbeendeceivedattheexpenseofmuchcostandtrouble。Amaleanimalmaysometimesbepairedwithhisdaughter，granddaughter，andsoon，evenforsevengenerations，withoutanymanifestbadresult:buttheexperimenthasneverbeentriedofmatchingbrothersandsisters，whichisconsideredtheclosestformofinterbreeding，foranequalnumberofgenerations。Thereisgoodreasontobelievethatbykeepingthemembersofthesamefamilyindistinctbodies，especiallyifexposedtosomewhatdifferentconditionsoflife，andbyoccasionallycrossingthesefamilies，theevilresultsofinterbreedingmaybemuchdiminishedorquiteeliminated。Theseresultsarelossofconstitutionalvigour，size，andfertility;butthereisnonecessarydeteriorationinthegeneralformofthebody，orinothergoodqualities。Wehaveseenthatwithpigsfirst—rateanimalshavebeenproducedafterlong—continuedcloseinterbreeding，thoughtheyhadbecomeextremelyinfertilewhenpairedwiththeirnearrelations。Thelossoffertility，whenitoccurs，seemsnevertobeabsolute，butonlyrelativetoanimalsofthesameblood;sothatthissterilityistoacertainextentanalogouswiththatofself—impotentplantswhichcannotbefertilisedbytheirownpollen，butareperfectlyfertilewithpollenofanyotherindividualofthesamespecies。Thefactofinfertilityofthispeculiarnaturebeingoneoftheresultsoflong—continuedinterbreeding，showsthatinterbreedingdoesnotactmerelybycombiningandaugmentingvariousmorbidtendenciescommontobothparents;foranimalswithsuchtendencies，ifnotatthetimeactuallyill，cangenerallypropagatetheirkind。Althoughoffspringdescendedfromthenearestblood—relationsarenotnecessarilydeterioratedinstructure，yetsomeauthorsbelievethattheyareeminentlyliabletomalformations;andthisisnotimprobable，aseverythingwhichlessensthevitalpowersactsinthismanner。Instancesofthiskindhavebeenrecordedinthecaseofpigs，bloodhounds，andsomeotheranimals。
　　Finally，whenweconsiderthevariousfactsnowgivenwhichplainlyshowthatgoodfollowsfromcrossing，andlessplainlythatevilfollowsfromcloseinterbreeding，andwhenwebearinmindthatwithverymanyorganismselaborateprovisionshavebeenmadefortheoccasionalunionofdistinctindividuals，theexistenceofagreatlawofnatureisalmostproved;namely，thatthecrossingofanimalsandplantswhicharenotcloselyrelatedtoeachotherishighlybeneficialorevennecessary，andthatinterbreedingprolongedduringmanygenerationsisinjurious。
　　CHAPTER2。XVIII。
　　ONTHEADVANTAGESANDDISADVANTAGESOFCHANGEDCONDITIONSOFLIFE:STERILITY
　　FROMVARIOUSCAUSES。
　　ONTHEGOODDERIVEDFROMSLIGHTCHANGESINTHECONDITIONSOFLIFE。
　　STERILITYFROMCHANGEDCONDITIONS，INANIMALS，INTHEIRNATIVECOUNTRYANDIN
　　MENAGERIES。
　　MAMMALS，BIRDS，ANDINSECTS。
　　LOSSOFSECONDARYSEXUALCHARACTERSANDOFINSTINCTS。
　　CAUSESOFSTERILITY。
　　STERILITYOFDOMESTICATEDANIMALSFROMCHANGEDCONDITIONS。
　　SEXUALINCOMPATIBILITYOFINDIVIDUALANIMALS。
　　STERILITYOFPLANTSFROMCHANGEDCONDITIONSOFLIFE。
　　CONTABESCENCEOFTHEANTHERS。
　　MONSTROSITIESASACAUSEOFSTERILITY。
　　DOUBLEFLOWERS。
　　SEEDLESSFRUIT。
　　STERILITYFROMTHEEXCESSIVEDEVELOPMENTOFTHEORGANSOFVEGETATION。
　　FROMLONG—CONTINUEDPROPAGATIONBYBUDS。
　　INCIPIENTSTERILITYTHEPRIMARYCAUSEOFDOUBLEFLOWERSANDSEEDLESSFRUIT。
　　ONTHEGOODDERIVEDFROMSLIGHTCHANGESINTHECONDITIONSOFLIFE。
　　Inconsideringwhetheranyfactswereknownwhichmightthrowlightontheconclusionarrivedatinthelastchapter，namely，thatbenefitsensuefromcrossing，andthatitisalawofnaturethatallorganicbeingsshouldoccasionallycross，itappearedtomeprobablethatthegoodderivedfromslightchangesintheconditionsoflife，frombeingananalogousphenomenon，mightservethispurpose。Notwoindividuals，andstilllessnotwovarieties，areabsolutelyalikeinconstitutionandstructure;andwhenthegermofoneisfertilisedbythemaleelementofanother，wemaybelievethatitisactedoninasomewhatsimilarmannerasanindividualwhenexposedtoslightlychangedconditions。Now，everyonemusthaveobservedtheremarkableinfluenceonconvalescentsofachangeofresidence，andnomedicalmandoubtsthetruthofthisfact。Smallfarmerswhoholdbutlittlelandareconvincedthattheircattlederivegreatbenefitfromachangeofpasture。Inthecaseofplants，theevidenceisstrongthatagreatadvantageisderivedfromexchangingseeds，tubers，bulbs，andcuttingsfromonesoilorplacetoanotherasdifferentaspossible。
　　[Thebeliefthatplantsarethusbenefited，whetherornotwellfounded，hasbeenfirmlymaintainedfromthetimeofColumella，whowroteshortlyaftertheChristianera，tothepresentday;anditnowprevailsinEngland，France，andGermany。（18/1。ForEnglandseebelow。ForGermanyseeMetzger’Getreidearten’
　　1841s。63。ForFranceLoiseleur—Deslongchamps（’Consid。surlesCereales’
　　1843page200）givesnumerousreferencesonthissubject。ForSouthernFranceseeGodron’FlorulaJuvenalis’1854page28。）Asagaciousobserver，Bradley，writingin1724（18/2。’AGeneralTreatiseofHusbandry’volume3page58。），says，"WhenweoncebecomeMastersofagoodSortofSeed，weshouldatleastputitintoTwoorThreeHands，wheretheSoilsandSituationsareasdifferentaspossible;andeveryYearthePartiesshouldchangewithoneanother;bywhichMeans，IfindtheGoodnessoftheSeedwillbemaintainedforseveralYears。ForWantofthisUsemanyFarmershavefailedintheirCropsandbeengreatLosers。"Hethengiveshisownpracticalexperienceonthishead。Amodernwriter（18/3。’Gardener’sChronicleandAgricult。Gazette’
　　1858page247;andforthesecondstatement，Ibid1850page702。OnthissamesubjectseealsoRev。D。Walker’PrizeEssayofHighlandAgricult。Soc。’
　　volume2page200。AlsoMarshall’MinutesofAgriculture’November1775。）
　　asserts，"Nothingcanbemoreclearlyestablishedinagriculturethanthatthecontinualgrowthofanyonevarietyinthesamedistrictmakesitliabletodeteriorationeitherinqualityorquantity。"Anotherwriterstatesthathesowedclosetogetherinthesamefieldtwolotsofwheat—seed，theproductofthesameoriginalstock，oneofwhichhadbeengrownonthesamelandandtheotheratadistance，andthedifferenceinfavourofthecropfromthelatterseedwasremarkable。AgentlemaninSurreywhohaslongmadeithisbusinesstoraisewheattosellforseed，andwhohasconstantlyrealisedinthemarkethigherpricesthanothers，assuresmethathefindsitindispensablecontinuallytochangehisseed;andthatforthispurposehekeepstwofarmsdifferingmuchinsoilandelevation。
　　Withrespecttothetubersofthepotato，Ifindthatatthepresentdaythepracticeofexchangingsetsisalmosteverywherefollowed。ThegreatgrowersofpotatoesinLancashireformerlyusedtogettubersfromScotland，buttheyfoundthat"achangefromthemoss—lands，andviceversa，wasgenerallysufficient。"InformertimesinFrancethecropofpotatoesintheVosgeshadbecomereducedinthecourseoffiftyorsixtyyearsintheproportionfrom120—150to30—40bushels;andthefamousOberlinattributedthesurprisinggoodwhichheeffectedinlargeparttochangingthesets。（18/4。Oberlin’Memoirs’Englishtranslationpage73。ForLancashireseeMarshall’ReviewofReports’1808page295。）
　　Awell—knownpracticalgardener，Mr。Robson（18/5。’CottageGardener’1856
　　page186。ForMr。Robson’ssubsequentstatementssee’JournalofHorticulture’
　　February18，1866page121。ForMr。Abbey’sremarksongraftingetc。IbidJuly18，1865page44。）positivelystatesthathehashimselfwitnesseddecidedadvantagefromobtainingbulbsoftheonion，tubersofthepotato，andvariousseeds，allofthesamekind，fromdifferentsoilsanddistantpartsofEngland。Hefurtherstatesthatwithplantspropagatedbycuttings，aswiththePelargonium，andespeciallytheDahlia，manifestadvantageisderivedfromgettingplantsofthesamevariety，whichhavebeencultivatedinanotherplace;or，"wheretheextentoftheplaceallows，totakecuttingsfromonedescriptionofsoiltoplantonanother，soastoaffordthechangethatseemssonecessarytothewell—beingoftheplants。"Hemaintainsthatafteratimeanexchangeofthisnatureis"forcedonthegrower，whetherhebepreparedforitornot。"Similarremarkshavebeenmadebyanotherexcellentgardener，Mr。Fish，namely，thatcuttingsofthesamevarietyofCalceolaria，whichheobtainedfromaneighbour，"showedmuchgreatervigourthansomeofhisownthatwere"treatedinexactlythesamemanner，"andheattributedthissolelytohisownplantshavingbecome"toacertainextentwornoutortiredoftheirquarters。"Somethingofthiskindapparentlyoccursingraftingandbuddingfruit—trees;for，accordingtoMr。Abbey，graftsorbudsgenerallytakewithgreaterfacilityonadistinctvarietyorevenspecies，oronastockpreviouslygrafted，thanonstocksraisedfromseedsofthevarietywhichistobegrafted;andhebelievesthiscannotbealtogetherexplainedbythestocksinquestionbeingbetteradaptedtothesoilandclimateoftheplace。Itshould，however，beadded，thatvarietiesgraftedorbuddedonverydistinctkinds，thoughtheymaytakemorereadilyandgrowatfirstmorevigorouslythanwhengraftedoncloselyalliedstocks，afterwardsoftenbecomeunhealthy。
　　IhavestudiedM。Tessier’scarefulandelaborateexperiments（18/6。’Mem。del’Acad。desSciences’1790page209。）madetodisprovethecommonbeliefthatgoodisderivedfromachangeofseed;andhecertainlyshowsthatthesameseedmaywithcarebecultivatedonthesamefarm（itisnotstatedwhetheronexactlythesamesoil）fortenconsecutiveyearswithoutloss。Anotherexcellentobserver，ColonelLeCouteur（18/7。’OntheVarietiesofWheat’page52。）hascometothesameconclusion;butthenheexpresslyadds，ifthesameseedbeused，"thatwhichisgrownonlandmanuredfromthemixenoneyearbecomesseedforlandpreparedwithlime，andthatagainbecomesseedforlanddressedwithashes，thenforlanddressedwithmixedmanure，andsoon。"Butthisineffectisasystematicexchangeofseed，withinthelimitsofthesamefarm。]
　　Onthewholethebelief，whichhaslongbeenheldbymanycultivators，thatgoodfollowsfromexchangingseed，tubers，etc。，seemstobefairlywellfounded。Itseemshardlycrediblethattheadvantagethusderivedcanbeduetotheseeds，especiallyifverysmallones，obtaininginonesoilsomechemicalelementdeficientintheotherandinsufficientquantitytoinfluencethewholeafter—growthoftheplant。Asplantsafteroncegerminatingarefixedtothesamespot，itmighthavebeenanticipatedthattheywouldshowthegoodeffectsofachangemoreplainlythandoanimalswhichcontinuallywanderabout;andthisapparentlyisthecase。Lifedependingon，orconsistingin，anincessantplayofthemostcomplexforces，itwouldappearthattheiractionisinsomewaystimulatedbyslightchangesinthecircumstancestowhicheachorganismisexposed。Allforcesthroughoutnature，asMr。HerbertSpencer（18/8。Mr。Spencerhasfullyandablydiscussedthiswholesubjectinhis’PrinciplesofBiology’1864volume2chapter10。Inthefirsteditionofmy’OriginofSpecies’1859page267，Ispokeofthegoodeffectsfromslightchangesintheconditionsoflifeandfromcross—breeding，andoftheevileffectsfromgreatchangesintheconditionsandfromcrossingwidelydistinctforms，asaseriesoffacts"connectedtogetherbysomecommonbutunknownbond，whichisessentiallyrelatedtotheprincipleoflife。）
　　remarks，tendtowardsanequilibrium，andforthelifeofeachorganismitisnecessarythatthistendencyshouldbechecked。Theseviewsandtheforegoingfactsprobablythrowlight，ontheonehand，onthegoodeffectsofcrossingthebreed，forthegermwillbethusslightlymodifiedoractedonbynewforces;andontheotherhand，ontheevileffectsofcloseinterbreedingprolongedduringmanygenerations，duringwhichthegermwillbeactedonbyamalehavingalmostidenticallythesameconstitution。
　　STERILITYFROMCHANGEDCONDITIONSOFLIFE。
　　Iwillnowattempttoshowthatanimalsandplants，whenremovedfromtheirnaturalconditions，areoftenrenderedinsomedegreeinfertileorcompletelybarren;andthisoccursevenwhentheconditionshavenotbeengreatlychanged。Thisconclusionisnotnecessarilyopposedtothatatwhichwehavejustarrived，namely，thatlesserchangesofotherkindsareadvantageoustoorganicbeings。Ourpresentsubjectisofsomeimportance，fromhavinganintimateconnectionwiththecausesofvariability。Indirectlyitperhapsbearsonthesterilityofspecieswhencrossed:foras，ontheonehand，slightchangesintheconditionsoflifearefavourabletoplantsandanimals，andthecrossingofvarietiesaddstothesize，vigour，andfertilityoftheiroffspring;so，ontheotherhand，certainotherchangesintheconditionsoflifecausesterility;andasthislikewiseensuesfromcrossingmuch—modifiedformsorspecies，wehaveaparallelanddoubleseriesoffacts，whichapparentlystandincloserelationtoeachother。
　　Itisnotoriousthatmanyanimals，thoughperfectlytamed，refusetobreedincaptivity。IsidoreGeoffroySt。—Hilaire（18/9。’EssaisdeZoologieGenerale’
　　1841page256。）consequentlyhasdrawnabroaddistinctionbetweentamedanimalswhichwillnotbreedundercaptivity，andtrulydomesticatedanimalswhichbreedfreely——generallymorefreely，asshowninthesixteenthchapter，thaninastateofnature。Itispossibleandgenerallyeasytotamemostanimals;butexperiencehasshownthatitisdifficulttogetthemtobreedregularly，orevenatall。Ishalldiscussthissubjectindetail;butwillgiveonlythosecaseswhichseemmostillustrative。Mymaterialsarederivedfromnoticesscatteredthroughvariousworks，andespeciallyfromaReport，kindlydrawnupformebytheofficersoftheZoologicalSocietyofLondon，whichhasespecialvalue，asitrecordsallthecases，duringnineyearsfrom1838—46，inwhichtheanimalswereseentocouplebutproducednooffspring，aswellasthecasesinwhichtheynever，asfarasknown，coupled。ThisMS。
　　ReportIhavecorrectedbytheannualReportssubsequentlypublisheduptotheyear1865。（18/10。Sincetheappearanceofthefirsteditionofthiswork，Mr。
　　Sclaterhaspublished（’Proc。Zoolog。Soc。’1868page623）alistofthespeciesofmammalswhichhavebredinthegardensfrom1848to1867inclusive。
　　OftheArtiodactyla85specieshavebeenkept，andofthese1speciesin1。9
　　havebredatleastonceduringthe20years;of28Marsupialia，1in2。5havebred;of74Carnivora，1in3。0havebred;of52Rodentia，1in4。7havebred;
　　andofQuadrumana75specieshavebeenkept，and1in6。2havebred。）Manyfactsaregivenonthebreedingoftheanimalsinthatmagnificentwork，’GleaningsfromtheMenageriesofKnowsleyHall’byDr。Gray。Imade，also，particularinquiriesfromtheexperiencedkeeperofthebirdsintheoldSurreyZoologicalGardens。Ishouldpremisethataslightchangeinthetreatmentofanimalssometimesmakesagreatdifferenceintheirfertility;
　　anditisprobablethattheresultsobservedindifferentmenagerieswoulddiffer。Indeed，someanimalsinourZoologicalGardenshavebecomemoreproductivesincetheyear1846。Itis，also，manifestfromF。Cuvier’saccountoftheJardindesPlantes（18/11。DuRut’AnnalesduMuseum’1807tome9page120。）thattheanimalsformerlybredmuchlessfreelytherethanwithus;forinstance，intheDucktribe，whichishighlyprolific，onlyonespecieshadatthatperiodproducedyoung。
　　[Themostremarkablecases，however，areaffordedbyanimalskeptintheirnativecountry，which，thoughperfectlytamed，quitehealthy，andallowedsomefreedom，areabsolutelyincapableofbreeding。Rengger（18/12。’SaugethierevonParaguay’1830s。49，106，118，124，201，208，249，265，327。），whoinParaguayparticularlyattendedtothissubject，specifiessixquadrupedsinthiscondition;andhementionstwoorthreeotherswhichmostrarelybreed。
　　Mr。Bates，inhisadmirableworkontheAmazons，stronglyinsistsonsimilarcases（18/13。’TheNaturalistontheAmazons’1863volume1pages99，193;
　　volume2page113。）;andheremarks，thatthefactofthoroughlytamednativemammalsandbirdsnotbreedingwhenkeptbytheIndians，cannotbewhollyaccountedforbytheirnegligenceorindifference，fortheturkeyandfowlarekeptandbredbyvariousremotetribes。Inalmosteverypartoftheworld——forinstance，intheinteriorofAfrica，andinseveralofthePolynesianislands——thenativesareextremelyfondoftamingtheindigenousquadrupedsandbirds;buttheyrarelyorneversucceedingettingthemtobreed。
　　Themostnotoriouscaseofananimalnotbreedingincaptivityisthatoftheelephant。ElephantsarekeptinlargenumbersintheirnativeIndianhome，livetooldage，andarevigorousenoughfortheseverestlabour;yet，withaveryfewexceptions，theyhaveneverbeenknowneventocouple，thoughbothmalesandfemaleshavetheirproperperiodicalseasons。If，however，weproceedalittleeastwardtoAva，wehearfromMr。Crawfurd（18/14。’EmbassytotheCourtofAva’volume1page534。）thattheir"breedinginthedomesticstate，oratleastinthehalf—domesticstateinwhichthefemaleelephantsaregenerallykept，isofeverydayoccurrence;"andMr。Crawfurdinformsmethathebelievesthatthedifferencemustbeattributedsolelytothefemalesbeingallowedtoroamtheforestwithsomedegreeoffreedom。Thecaptiverhinoceros，ontheotherhand，seemsfromBishopHeber’saccount（18/15。
　　’Journal’volume1page213。）tobreedinIndiafarmorereadilythantheelephant。FourwildspeciesofthehorsegenushavebredinEurope，thoughhereexposedtoagreatchangeintheirnaturalhabitsoflife;butthespecieshavegenerallybeencrossedonewithanother。Mostofthemembersofthepigfamilybreedreadilyinourmenageries;eventheRedRiverhog（Potamochoeruspenicillatus），fromtheswelteringplainsofWestAfrica，hasbredtwiceintheZoologicalGardens。HerealsothePeccary（Dicotylestorquatus）hasbredseveraltimes;butanotherspecies，theD。labiatus，thoughrenderedsotameastobehalf—domesticated，issaidtobreedsorarelyinitsnativecountryofParaguay，thataccordingtoRengger（18/16。
　　’Saugethiere’s。327。）thefactrequiresconfirmation。Mr。Batesremarksthatthetapir，thoughoftenkepttameinAmazoniabytheIndians，neverbreeds。
　　RuminantsgenerallybreedquitefreelyinEngland，thoughbroughtfromwidelydifferentclimates，asmaybeseenintheAnnualReportsoftheZoologicalGardens，andintheGleaningsfromLordDerby’smenagerie。
　　TheCarnivora，withtheexceptionofthePlantigradedivision，breed（thoughwithcapriciousexceptions）abouthalfasfreelyasruminants。ManyspeciesofFelidaehavebredinvariousmenageries，althoughimportedfromdiverseclimatesandcloselyconfined。Mr。Bartlett，thepresentsuperintendentoftheZoologicalGardens（18/17。OntheBreedingoftheLargerFelidae’Proc。
　　Zoolog。Soc。’1861page140。）remarksthatthelionappearstobreedmorefrequentlyandtobringforthmoreyoungatabirththananyotherspeciesofthefamily。Headdsthatthetigerhasrarelybred;"butthereareseveralwell—authenticatedinstancesofthefemaletigerbreedingwiththelion。"
　　Strangeasthefactmayappear，manyanimalsunderconfinementunitewithdistinctspeciesandproducehybridsquiteasfreelyas，orevenmorefreelythan，withtheirownspecies。OninquiringfromDr。Falconerandothers，itappearsthatthetigerwhenconfinedinIndiadoesnotbreed，thoughithasbeenknowntocouple。Thechetah（Felisjubata）hasneverbeenknownbyMr。
　　BartletttobreedinEngland，butithasbredatFrankfort;nordoesitbreedinIndia，whereitiskeptinlargenumbersforhunting;butnopainswouldbetakentomakethembreed，asonlythoseanimalswhichhavehuntedforthemselvesinastateofnatureareserviceableandworthtraining。（18/18。
　　Sleeman’s’RamblesinIndia’volume2page10。）AccordingtoRengger，twospeciesofwildcatsinParaguay，thoughthoroughlytamed，haveneverbred。
　　AlthoughsomanyoftheFelidaebreedreadilyintheZoologicalGardens，yetconceptionbynomeansalwaysfollowsunion:inthenine—yearReport，variousspeciesarespecifiedwhichwereobservedtocoupleseventy—threetimes，andnodoubtthismusthavepassedmanytimesunnoticed;yetfromtheseventy—
　　threeunionsonlyfifteenbirthsensued。TheCarnivoraintheZoologicalGardenswereformerlylessfreelyexposedtotheairandcoldthanatpresent，andthischangeoftreatment，asIwasassuredbytheformersuperintendent，Mr。Miller，greatlyincreasedtheirfertility。Mr。Bartlett，andtherecannotbeamorecapablejudge，says，"itisremarkablethatlionsbreedmorefreelyintravellingcollectionsthanintheZoologicalGardens;probablytheconstantexcitementandirritationproducedbymovingfromplacetoplace，orchangeofair，mayhaveconsiderableinfluenceinthematter。"
　　ManymembersoftheDogfamilybreedreadilywhenconfined。TheDholeisoneofthemostuntamableanimalsinIndia，yetapairkepttherebyDr。Falconerproducedyoung。Foxes，ontheotherhand，rarelybreed，andIhaveneverheardofsuchanoccurrencewiththeEuropeanfox:thesilverfoxofNorthAmerica（Canisargentatus），however，hasbredseveraltimesintheZoologicalGardens。
　　Eventheotterhasbredthere。Everyoneknowshowreadilythesemi—
　　domesticatedferretbreeds，thoughshutupinmiserablysmallcages;butotherspeciesofViverraandParadoxurusabsolutelyrefusetobreedintheZoologicalGardens。TheGenettahasbredbothhereandintheJardindesPlantes，andproducedhybrids。TheHerpestesfasciatushaslikewisebred;butIwasformerlyassuredthattheH。griseus，thoughmanywerekeptintheGardens，neverbred。
　　ThePlantigradeCarnivorabreedunderconfinementmuchlessfreelythanotherCarnivora，althoughnoreasoncanbeassignedforthisfact。Inthenine—yearReportitisstatedthatthebearshadbeenseenintheZoologicalGardenstocouplefreely，butpreviouslyto1848hadmostrarelyconceived。IntheReportspublishedsincethisdatethreespecieshaveproducedyoung（hybridsinonecase），and，wonderfultorelate，thewhitePolarbearhasproducedyoung。Thebadger（Melestaxus）hasbredseveraltimesintheGardens;butI
　　havenotheardofthisoccurringelsewhereinEngland，andtheeventmustbeveryrare，foraninstanceinGermanyhasbeenthoughtworthrecording。
　　（18/19。Wiegmann’Archiv。furNaturgesch。’1837s。162。）InParaguaythenativeNasua，thoughkeptinpairsduringmanyyearsandperfectlytamed，hasneverbeenknown，accordingtoRengger，tobreedorshowanysexualpassion;
　　nor，asIhearfromMr。Bates，doesthisanimal，ortheCercoleptes，breedinAmazonia。Twootherplantigradegenera，ProcyonandGulo，thoughoftenkepttameinParaguay，neverbreedthere。IntheZoologicalGardensspeciesofNasuaandProcyonhavebeenseentocouple;buttheydidnotproduceyoung。
　　Asdomesticatedrabbits，guinea—pigs，andwhitemicebreedsoabundantlywhencloselyconfinedundervariousclimates，itmighthavebeenthoughtthatmostothermembersoftheRodentorderwouldhavebredincaptivity，butthisisnotthecase。Itdeservesnotice，asshowinghowthecapacitytobreedsometimesgoesbyaffinity，thattheonenativerodentofParaguay，whichtherebreedsFREELYandhasyieldedsuccessivegenerations，istheCaviaaperea;andthisanimalissocloselyalliedtotheguinea—pig，thatithasbeenerroneouslythoughttobetheparentform。（18/20。Rengger’Saugethiere’
　　etc。s。276。Ontheparentageoftheguinea—pig，seealsoIsid。GeoffroySt。—
　　Hilaire’Hist。Nat。Gen。’IsenttoMr。H。DennyofLeedsthelicewhichI
　　collectedfromthewildapereainLaPlata，andheinformsmethattheybelongtoagenusdistinctfromthosefoundontheguinea—pig。Thisisimportantevidencethattheapereaisnottheparentoftheguinea—pig;andisworthgiving，assomeauthorserroneouslysupposethattheguinea—pigsincebeingdomesticatedhasbecomesterilewhencrossedwiththeaperea。）IntheZoologicalGardens，somerodentshavecoupled，buthaveneverproducedyoung;
　　somehaveneithercouplednorbred;butafewhavebred，astheporcupinemorethanonce，theBarbarymouse，lemming，chinchilla，andagouti（Dasyproctaaguti）severaltimes。ThislatteranimalhasalsoproducedyounginParaguay，thoughtheywereborndeadandill—formed;butinAmazonia，accordingtoMr。
　　Bates，itneverbreeds，thoughoftenkepttameaboutthehouses。Nordoesthepaca（Coelogenyspaca）breedthere。Thecommonharewhenconfinedhas，I
　　believe，neverbredinEurope;though，accordingtoarecentstatement，ithascrossedwiththerabbit。（18/21。AlthoughtheexistenceoftheLeporides，asdescribedbyDr。Broca（’JournaldePhys。’tome2page370），hasbeenpositivelydenied，yetDr。Pigeaux（’AnnalsandMag。ofNat。Hist。’volume20
　　1867page75）affirmsthatthehareandrabbithaveproducedhybrids。）Ihaveneverheardofthedormousebreedinginconfinement。Butsquirrelsofferamorecuriouscase:withoneexception，nospecieshasbredintheZoologicalGardens，yetasmanyasfourteenindividualsofS。palmarumwerekepttogetherduringseveralyears。TheS。cinerahasbeenseentocouple，butitdidnotproduceyoung;norhasthisspecies，whenrenderedextremelytameinitsnativecountry，NorthAmerica，beeneverknowntobreed。（18/22。’QuadrupedsofNorthAmerica’byAudubonandBachman1846page268。）AtLordDerby’smenageriesquirrelsofmanykindswerekeptinnumbers，butMr。Thompson，thesuperintendent，toldmethatnonehadeverbredthere，orelsewhereasfarasheknew。IhaveneverheardoftheEnglishsquirrelbreedinginconfinement。
　　ButthespecieswhichhasbredmorethanonceintheZoologicalGardensistheonewhichperhapsmighthavebeenleastexpected，namely，theflyingsquirrel（Sciuropterusvolucella）:ithas，also，bredseveraltimesnearBirmingham;
　　butthefemaleneverproducedmorethantwoyoungatabirth，whereasinitsnativeAmericanhomeshebearsfromthreetosixyoung。（18/23。Loudon’s’Mag。
　　ofNat。Hist。’volume91836page571;AudubonandBachman’QuadrupedsofNorthAmerica’page221。）
　　Monkeys，inthenine—yearReportfromtheZoologicalGardens，arestatedtounitemostfreely，butduringthisperiod，thoughmanyindividualswerekept，therewereonlysevenbirths。IhaveheardofonlyoneAmericanmonkey，theOuistiti，breedinginEurope。（18/24。Flourens’Del’Instinct’etc。1845page88。）AMacacus，accordingtoFlourens，bredinParis;andmorethanonespeciesofthisgenushasproducedyounginLondon，especiallytheMacacusrhesus，whicheverywhereshowsaspecialcapacitytobreedunderconfinement。
　　HybridshavebeenproducedbothinParisandLondonfromthissamegenus。TheArabianbaboon，orCynocephalushamadryas（18/25。See’AnnualReportsZoolog。
　　Soc。’1855，1858，1863，1864;’Times’newspaperAugust10，1847;Flourens’Del’Instinct’page85。），andaCercopithecushavebredintheZoologicalGardens，andthelatterspeciesattheDukeofNorthumberland’s。SeveralmembersofthefamilyofLemurshaveproducedhybridsintheZoologicalGardens。Itismuchmoreremarkablethatmonkeysveryrarelybreedwhenconfinedintheirnativecountry;thustheCay（Cebusazara）isfrequentlyandcompletelytamedinParaguay，butRengger（18/26。’Saugethiere’etc。s。34，49。）saysthatitbreedssorarely，thatheneversawmorethantwofemaleswhichhadproducedyoung。AsimilarobservationhasbeenmadewithrespecttothemonkeyswhicharefrequentlytamedbytheaboriginesinBrazil。（18/27。
　　Art。Brazil’PennyCyclop。’page363。）InAmazonia，theseanimalsaresooftenkeptinatamestate，thatMr。BatesinwalkingthroughthestreetsofParacountedthirteenspecies;but，asheasserts，theyhaveneverbeenknowntobreedincaptivity。（18/28。’TheNaturalistontheAmazons’volume1page99。）
　　BIRDS。
　　Birdsofferinsomerespectsbetterevidencethanquadrupeds，fromtheirbreedingmorerapidlyandbeingkeptingreaternumbers。（18/29。AlistofthespeciesofbirdswhichhavebredintheZoologicalGardensfrom1848to1867
　　inclusivehasbeenpublishedbyMr。Sclaterin’Proc。Zoolog。Soc。’1869page626，sincethefirsteditionofthisworkappeared。OfColumbae51specieshavebeenkept，andofAnseres80species，andinboththesefamilies1
　　speciesin2。6havebredatleastonceinthe20years。OfGallinae83specieshavebeenkeptand1in27havebred;of57Grallae1in9havebred;of110
　　Prehensores1in22havebred;of178Passeres1in25。4havebred;of94
　　Accipitres1in47havebred;of25Picariaeandof35Herodionesnotonespeciesineithergrouphasbred。）Wehaveseenthatcarnivorousanimalsaremorefertileunderconfinementthanmostothermammals。Thereverseholdsgoodwithcarnivorousbirds。Itissaid（18/30。’Encyclop。ofRuralSports’page691。）thatasmanyaseighteenspecieshavebeenusedinEuropeforhawking，andseveralothersinPersiaandIndia（18/31。AccordingtoSirA。Burnes’Cabool’etc。page51，eightspeciesareusedforhawkinginSinde。）;theyhavebeenkeptintheirnativecountryinthefinestcondition，andhavebeenflownduringsix，eight，ornineyears（18/32。Loudon’s’Mag。ofNat。Hist。’
　　volume61833page110。）;yetthereisnorecordoftheirhavingeverproducedyoung。Asthesebirdswereformerlycaughtwhilstyoung，atgreatexpense，beingimportedfromIceland，Norway，andSweden，therecanbelittledoubtthat，ifpossible，theywouldhavebeenpropagated。IntheJardindesPlantes，nobirdofpreyhasbeenknowntocouple。（18/33。F。Cuvier’Annal。duMuseum’
　　tome9page128。）Nohawk，vulture，orowlhaseverproducedfertileeggsintheZoologicalGardens，orintheoldSurreyGardens，withtheexception，intheformerplaceononeoccasion，ofacondorandakite（Milvusniger）。Yetseveralspecies，namely，theAquilafusca，Haliaetusleucocephalus，Falcotinnunculus，F。subbuteo，andButeovulgaris，havebeenseentocoupleintheZoologicalGardens。Mr。Morris（18/34。’TheZoologist’volume7—81849—50page2648。）mentionsasauniquefactthatakestrel（Falcotinnunculus）bredinanaviary。TheonekindofowlwhichhasbeenknowntocoupleintheZoologicalGardenswastheEagleOwl（Bubomaximus）;andthisspeciesshowsaspecialinclinationtobreedincaptivity;forapairatArundelCastle，keptmorenearlyinastateofnature"thaneverfelltothelotofananimaldeprivedofitsliberty"（18/35。Knox’OrnithologicalRamblesinSussex’page91。），actuallyrearedtheiryoung。Mr。Gurneyhasgivenanotherinstanceofthissameowlbreedinginconfinement;andherecordsthecaseofasecondspeciesofowl，theStrixpasserina，breedingincaptivity。（18/36。’TheZoologist’
　　volume7—81849—50page2566;volume9—101851—2page3207。）
　　Ofthesmallergraminivorousbirds，manykindshavebeenkepttameintheirnativecountries，andhavelivedlong;yet，asthehighestauthorityoncage—
　　birds（18/37。Bechstein’Naturgesch。derStubenvogel’1840s。20。）remarks，theirpropagationis"uncommonlydifficult。"Thecanary—birdshowsthatthereisnoinherentdifficultyinthesebirdsbreedingfreelyinconfinement;andAudubonsays（18/38。’OrnithologicalBiography’volume5page517。）thattheFringilla（Spiza）cirisofNorthAmericabreedsasperfectlyasthecanary。
　　Thedifficultywiththemanyfincheswhichhavebeenkeptinconfinementisallthemoreremarkableasmorethanadozenspeciescouldbenamedwhichhaveyieldedhybridswiththecanary;buthardlyanyofthese，withtheexceptionofthesiskin（Fringillaspinus），havereproducedtheirownkind。Eventhebullfinch（Loxiapyrrhula）hasbredasfrequentlywiththecanary，thoughbelongingtoadistinctgenus，aswithitsownspecies。（18/39。Acaseisrecordedin’TheZoologist’volume1—21843—45page453。Forthesiskinbreeding，volume3—41845—46page1075。Bechstein’Stubenvogel’s。139speaksofbullfinchesmakingnests，butrarelyproducingyoung。）Withrespecttotheskylark（Alaudaarvensis），Ihaveheardofbirdslivingforsevenyearsinanaviary，whichneverproducedyoung;andagreatLondonbird—fancierassuredmethathehadneverknownaninstanceoftheirbreeding;neverthelessonecasehasbeenrecorded。（18/40。Yarrell’Hist。BritishBirds’1839volume1page412。）Inthenine—yearReportfromtheZoologicalSociety，twenty—fourinsessorialspeciesareenumeratedwhichhadnotbred，andoftheseonlyfourwereknowntohavecoupled。
　　Parrotsaresingularlylong—livedbirds;andHumboldtmentionsthecuriousfactofaparrotinSouthAmerica，whichspokethelanguageofanextinctIndiantribe，sothatthisbirdpreservedthesolerelicofalostlanguage。
　　Eveninthiscountrythereisreasontobelieve（18/41。Loudon’s’Mag。ofNat。
　　History’volume191836page347。）thatparrotshavelivedtotheageofnearlyonehundredyears;yettheybreedsorarely，thoughmanyhavebeenkeptinEurope，thattheeventhasbeenthoughtworthrecordinginthegravestpublications。（18/42。’MemoiresduMuseumd’Hist。Nat。’tome10page314:fivecasesofparrotsbreedinginFrancearehererecorded。Seealso’ReportBrit。
　　Assoc。Zoolog。’1843。）Nevertheless，whenMr。BuxtonturnedoutalargenumberofparrotsinNorfolk，threepairsbredandrearedtenyoungbirdsinthecourseoftwoseasons;andthissuccessmaybeattributedtotheirfreelife。
　　（18/43。’AnnalsandMag。ofNat。Hist。’November1868page311。）AccordingtoBechstein（18/44。’Stubenvogel’s。105，83。）theAfricanPsittacuserithacusbreedsoftenerthananyotherspeciesinGermany:theP。macoaoccasionallylaysfertileeggs，butrarelysucceedsinhatchingthem;thisbird，however，hastheinstinctofincubationsometimessostronglydeveloped，thatitwillhatchtheeggsoffowlsorpigeons。IntheZoologicalGardensandintheoldSurreyGardenssomefewspecieshavecoupled，but，withtheexceptionofthreespeciesofparakeets，nonehavebred。ItisamuchmoreremarkablefactthatinGuianaparrotsoftwokinds，asIaminformedbySirR。Schomburgk，areoftentakenfromthenestsbytheIndiansandrearedinlargenumbers;theyaresotamethattheyflyfreelyaboutthehouses，andcomewhencalledtobefed，likepigeons;yethehasneverheardofasingleinstanceoftheirbreeding。（18/45。Dr。Hancockremarks（’Charlesworth’sMag。ofNat。Hist。’
　　volume21838page492）"itissingularthat，amongstthenumeroususefulbirdsthatareindigenoustoGuiana，nonearefoundtopropagateamongtheIndians;yetthecommonfowlisrearedinabundancethroughoutthecountry。"）
　　InJamaica，aresidentnaturalist，Mr。R。Hill（18/46。’AWeekatPertRoyal’
　　1855page7。），says，"nobirdsmorereadilysubmittohumandependencethantheparrot—tribe，butnoinstanceofaparrotbreedinginthistamelifehasbeenknownyet。"Mr。HillspecifiesanumberofothernativebirdskepttameintheWestIndies，whichneverbreedinthisstate。
　　Thegreatpigeonfamilyoffersastrikingcontrastwiththeparrots:inthenine—yearReportthirteenspeciesarerecordedashavingbred，and，whatismorenoticeable，onlytwowereseentocouplewithoutanyresult。SincetheabovedateeveryannualReportgivesmanycasesofvariouspigeonsbreeding。
　　Thetwomagnificentcrownedpigeons（Gouracoronataandvictoriae）producedhybrids;nevertheless，oftheformerspeciesmorethanadozenbirdswerekept，asIaminformedbyMr。Crawfurd，inaparkatPenang，underaperfectlywell—adaptedclimate，butneveroncebred。TheColumbamigratoriainitsnativecountry，NorthAmerica，invariablylaystwoeggs，butinLordDerby’smenagerienevermorethanone。ThesamefacthasbeenobservedwiththeC。
　　leucocephala。（18/47。Audubon’AmericanOrnithology’volume5pages552，557。）