AnotherandsmallerspeciesofFurnariusF。cunicularius，resemblestheoven-birdinthegeneralreddishtintofitsplumage，inapeculiarshrillreiteratedcry，andinanoddmannerofrunningbystarts。Fromitsaffinity，theSpaniardscallitCasaritaorlittlehousebuilder，althoughitsnidificationisquitedifferent。TheCasaritabuildsitsnestatthebottomofanarrowcylindricalhole，whichissaidtoextendhorizontallytonearlysixfeetunderground。Severalofthecountrypeopletoldme，thatwhenboys，theyhadattemptedtodigoutthenest，buthadscarcelyeversucceededingettingtotheendofthepassage。Thebirdchoosesanylowbankoffirmsandysoilbythesideofaroadorstream。HereatBahiaBlancathewallsroundthehousesarebuiltofhardenedmud，andInoticedthatone，whichenclosedacourtyardwhereIlodged，wasboredthroughbyroundholesinascoreofplaces。Onaskingtheownerthecauseofthishebitterlycomplainedofthelittlecasarita，severalofwhichIafterwardsobservedatwork。Itisrathercurioustofindhowincapablethesebirdsmustbeofacquiringanynotionofthickness，foralthoughtheywereconstantlyflittingoverthelowwall，theycontinuedvainlytoborethroughit，thinkingitanexcellentbankfortheirnests。Idonotdoubtthateachbird，asoftenasitcametodaylightontheoppositeside，wasgreatlysurprisedatthemarvellousfact。
Ihavealreadymentionednearlyallthemammaliacommoninthiscountry。
Ofarmadilloesthreespeciesoccurnamely，theDasypusminutusor_pichy_，theD。villosusor_peludo_，andthe_apar_。Thefirstextendstendegreesfurthersouththananyotherkind；afourthspecies，the_Mulita_，doesnotcomeasfarsouthasBahiaBlanca。Thefourspecieshavenearlysimilarhabits；the_peludo_，however，isnocturnal，whiletheotherswanderbydayovertheopenplains，feedingonbeetles，larvae，roots，andevensmallsnakes。The_apar_，commonlycalled_mataco_，isremarkablebyhavingonlythreemoveablebands；therestofitstesselatedcoveringbeingnearlyinflexible。Ithasthepowerofrollingitselfintoaperfectsphere，likeonekindofEnglishwoodlouse。Inthisstateitissafefromtheattackofdogs；forthedognotbeingabletotakethewholeinitsmouth，triestobiteoneside，andtheballslipsaway。Thesmoothhardcoveringofthe_mataco_offersabetterdefencethanthesharpspinesofthehedgehog。
The_pichy_prefersaverydrysoil；andthesand-dunesnearthecoast，whereformanymonthsitcannevertastewater，isitsfavouriteresort：
itoftentriestoescapenotice，bysquattingclosetotheground。Inthecourseofaday’sride，nearBahiaBlanca，severalweregenerallymetwith。
Theinstantonewasperceived，itwasnecessary，inordertocatchit，almosttotumbleoffone’shorse；forinsoftsoiltheanimalburrowedsoquickly，thatitshinderquarterswouldalmostdisappearbeforeonecouldalight。Itseemsalmostapitytokillsuchnicelittleanimals，forasaGauchosaid，whilesharpeninghisknifeonthebackofone，“Sontanmansos“theyaresoquiet。
Ofreptilestherearemanykinds：onesnakeaTrigonocephalus，orCophias[18]，fromthesizeofthepoisonchannelinitsfangs，mustbeverydeadly。Cuvier，inoppositiontosomeothernaturalists，makesthisasub-genusoftherattlesnake，andintermediatebetweenitandtheviper。Inconfirmationofthisopinion，Iobservedafact，whichappearstomeverycuriousandinstructive，asshowinghoweverycharacter，eventhoughitmaybeinsomedegreeindependentofstructure，hasatendencytovarybyslowdegrees。Theextremityofthetailofthissnakeisterminatedbyapoint，whichisveryslightlyenlarged；andastheanimalglidesalong，itconstantlyvibratesthelastinch；andthispartstrikingagainstthedrygrassandbrushwood，producesarattlingnoise，whichcanbedistinctlyheardatthedistanceofsixfeet。Asoftenastheanimalwasirritatedorsurprised，itstailwasshaken；andthevibrationswereextremelyrapid。
Evenaslongasthebodyretaineditsirritability，atendencytothishabitualmovementwasevident。ThisTrigonocephalushas，therefore，insomerespectsthestructureofaviper，withthehabitsofarattlesnake：
thenoise，however，beingproducedbyasimplerdevice。Theexpressionofthissnake’sfacewashideousandfierce；thepupilconsistedofaverticalslitinamottledandcopperyiris；thejawswerebroadatthebase，andthenoseterminatedinatriangularprojection。IdonotthinkIeversawanythingmoreugly，excepting，perhaps，someofthevampirebats。Iimaginethisrepulsiveaspectoriginatesfromthefeaturesbeingplacedinpositions，withrespecttoeachother，somewhatproportionaltothoseofthehumanface；andthusweobtainascaleofhideousness。
AmongsttheBatrachianreptiles，IfoundonlyonelittletoadPhryniscusnigricans，whichwasmostsingularfromitscolour。Ifweimagine，first，thatithadbeensteepedintheblackestink，andthen，whendry，allowedtocrawloveraboard，freshlypaintedwiththebrightestvermilion，soastocolourthesolesofitsfeetandpartsofitsstomach，agoodideaofitsappearancewillbegained。Ifithadbeenanunnamedspecies，surelyitoughttohavebeencalled_Diabolicus_，foritisafittoadtopreachintheearofEve。Insteadofbeingnocturnalinitshabits，asothertoadsare，andlivingindampobscurerecesses，itcrawlsduringtheheatofthedayaboutthedrysand-hillocksandaridplains，wherenotasingledropofwatercanbefound。Itmustnecessarilydependonthedewforitsmoisture；andthisprobablyisabsorbedbytheskin，foritisknown，thatthesereptilespossessgreatpowersofcutaneousabsorption。AtMaldonado，IfoundoneinasituationnearlyasdryasatBahiaBlanca，andthinkingtogiveitagreattreat，carriedittoapoolofwater；notonlywasthelittleanimalunabletoswim，butIthinkwithouthelpitwouldsoonhavebeendrowned。Oflizardsthereweremanykinds，butonlyoneProctotretusmultimaculatusremarkablefromitshabits。Itlivesonthebaresandneartheseacoast，andfromitsmottledcolour，thebrownishscalesbeingspeckledwithwhite，yellowishred，anddirtyblue，canhardlybedistinguishedfromthesurroundingsurface。Whenfrightened，itattemptstoavoiddiscoverybyfeigningdeath，withoutstretchedlegs，depressedbody，andclosedeyes：
iffurthermolested，itburiesitselfwithgreatquicknessintheloosesand。Thislizard，fromitsflattenedbodyandshortlegs，cannotrunquickly。
IwillhereaddafewremarksonthehybernationofanimalsinthispartofSouthAmerica。WhenwefirstarrivedatBahiaBlanca，September7th，1832，wethoughtnaturehadgrantedscarcelyalivingcreaturetothissandyanddrycountry。Bydigging，however，intheground，severalinsects，largespiders，andlizardswerefoundinahalf-torpidstate。
Onthe15th，afewanimalsbegantoappear，andbythe18ththreedaysfromtheequinox，everythingannouncedthecommencementofspring。Theplainswereornamentedbytheflowersofapinkwood-sorrel，wildpeas，cenotherae，andgeraniums；andthebirdsbegantolaytheireggs。NumerousLamellicornandHeteromerousinsects，thelatterremarkablefortheirdeeplysculpturedbodies，wereslowlycrawlingabout；whilethelizardtribe，theconstantinhabitantsofasandysoil，dartedaboutineverydirection。
Duringthefirstelevendays，whilstnaturewasdormant，themeantemperaturetakenfromobservationsmadeeverytwohoursonboardtheBeagle，was51
degs。；andinthemiddleofthedaythethermometerseldomrangedabove55degs。Ontheelevensucceedingdays，inwhichalllivingthingsbecamesoanimated，themeanwas58degs。，andtherangeinthemiddleoftheday7between60and70degs。Here，then，anincreaseofsevendegreesinmeantemperature，butagreateroneofextremeheat，wassufficienttoawakethefunctionsoflife。AtMonteVideo，fromwhichwehadjustbeforesailed，inthetwenty-threedaysincludedbetweenthe26thofJulyandthe19thofAugust，themeantemperaturefrom276observationswas58。4degs。；themeanhottestdaybeing65。5degs。，andthecoldest46degs。
Thelowestpointtowhichthethermometerfellwas41。5degs。，andoccasionallyinthemiddleofthedayitroseto69or70degs。Yetwiththishightemperature，almosteverybeetle，severalgeneraofspiders，snails，andland-shells，toadsandlizardswerealllyingtorpidbeneathstones。ButwehaveseenthatatBahiaBlanca，whichisfourdegreessouthwardandthereforewithaclimateonlyaverylittlecolder，thissametemperaturewitharatherlessextremeheat，wassufficienttoawakeallordersofanimatedbeings。
Thisshowshownicelythestimulusrequiredtoarousehybernatinganimalsisgovernedbytheusualclimateofthedistrict，andnotbytheabsoluteheat。Itiswellknownthatwithinthetropics，thehybernation，ormoreproperlyaestivation，ofanimalsisdeterminednotbythetemperature，butbythetimesofdrought。NearRiodeJaneiro，Iwasatfirstsurprisedtoobserve，that，afewdaysaftersomelittledepressionshadbeenfilledwithwater，theywerepeopledbynumerousfull-grownshellsandbeetles，whichmusthavebeenlyingdormant。Humboldthasrelatedthestrangeaccidentofahovelhavingbeenerectedoveraspotwhereayoungcrocodilelayburiedinthehardenedmud。Headds，“TheIndiansoftenfindenormousboas，whichtheycallUjiorwaterserpents，inthesamelethargicstate。Toreanimatethem，theymustbeirritatedorwettedwithwater。”
Iwillonlymentiononeotheranimal，azoophyteIbelieveVirgulariaPatagonica，akindofsea-pen。Itconsistsofathin，straight，fleshystem，withalternaterowsofpolypioneachside，andsurroundinganelasticstonyaxis，varyinginlengthfromeightinchestotwofeet。Thestematoneextremityistruncate，butattheotheristerminatedbyavermiformfleshyappendage。Thestonyaxiswhichgivesstrengthtothestemmaybetracedatthisextremityintoamerevesselfilledwithgranularmatter。
Atlowwaterhundredsofthesezoophytesmightbeseen，projectinglikestubble，withthetruncateendupwards，afewinchesabovethesurfaceofthemuddysand。Whentouchedorpulledtheysuddenlydrewthemselvesinwithforce，soasnearlyorquitetodisappear。Bythisaction，thehighlyelasticaxismustbebentatthelowerextremity，whereitisnaturallyslightlycurved；andIimagineitisbythiselasticityalonethatthezoophyteisenabledtoriseagainthroughthemud。Eachpolypus，thoughcloselyunitedtoitsbrethren，hasadistinctmouth，body，andtentacula。
Ofthesepolypi，inalargespecimen，theremustbemanythousands；yetweseethattheyactbyonemovement：theyhavealsoonecentralaxisconnectedwithasystemofobscurecirculation，andtheovaareproducedinanorgandistinctfromtheseparateindividuals。[19]Wellmayonebeallowedtoask，whatisanindividual？Itisalwaysinterestingtodiscoverthefoundationofthestrangetalesoftheoldvoyagers；andIhavenodoubtbutthatthehabitsofthisVirgulariaexplainonesuchcase。CaptainLancaster，inhisvoyage[20]in1601，narratesthatonthesea-sandsoftheIslandofSombrero，intheEastIndies，he“foundasmalltwiggrowinguplikeayoungtree，andonofferingtopluckitupitshrinksdowntotheground，andsinks，unlessheldveryhard。Onbeingpluckedup，agreatwormisfoundtobeitsroot，andasthetreegrowethingreatness，sodoththewormdiminish，andassoonasthewormisentirelyturnedintoatreeitrootethintheearth，andsobecomesgreat。ThistransformationisoneofthestrangestwondersthatIsawinallmytravels：forifthistreeispluckedup，whileyoung，andtheleavesandbarkstrippedoff，itbecomesahardstonewhendry，muchlikewhitecoral：thusisthiswormtwicetransformedintodifferentnatures。
Ofthesewegatheredandbroughthomemany。”
DuringmystayatBahiaBlanca，whilewaitingfortheBeagle，theplacewasinaconstantstateofexcitement，fromrumoursofwarsandvictories，betweenthetroopsofRosasandthewildIndians。OnedayanaccountcamethatasmallpartyformingoneofthepostasonthelinetoBuenosAyres，hadbeenfoundallmurdered。ThenextdaythreehundredmenarrivedfromtheColorado，underthecommandofCommandantMiranda。AlargeportionofthesemenwereIndiansmansos，ortame，belongingtothetribeoftheCaciqueBernantio。Theypassedthenighthere；anditwasimpossibletoconceiveanythingmorewildandsavagethanthesceneoftheirbivouac。
Somedranktilltheywereintoxicated；othersswallowedthesteamingbloodofthecattleslaughteredfortheirsuppers，andthen，beingsickfromdrunkenness，theycastitupagain，andwerebesmearedwithfilthandgore。
Namsimulexpletusdapibus，vinoquesepultusCerviceminflexamposuit，jacuitqueperantrumImmensus，saniemeructans，acfrustacruentaPersomnumcommixtamero。
Inthemorningtheystartedforthesceneofthemurder，withorderstofollowthe“rastro。”ortrack，evenifitledthemtoChile。WesubsequentlyheardthatthewildIndianshadescapedintothegreatPampas，andfromsomecausethetrackhadbeenmissed。Oneglanceattherastrotellsthesepeopleawholehistory。Supposingtheyexaminethetrackofathousandhorses，theywillsoonguessthenumberofmountedonesbyseeinghowmanyhavecantered；bythedepthoftheotherimpressions，whetheranyhorseswereloadedwithcargoes；bytheirregularityofthefootsteps，howfartired；bythemannerinwhichthefoodhasbeencooked，whetherthepursuedtravelledinhaste；bythegeneralappearance，howlongithasbeensincetheypassed。Theyconsiderarastrooftendaysorafortnight，quiterecentenoughtobehuntedout。WealsoheardthatMirandastruckfromthewestendoftheSierraVentana，inadirectlinetotheislandofCholechel，situatedseventyleaguesuptheRioNegro。Thisisadistanceofbetweentwoandthreehundredmiles，throughacountrycompletelyunknown。Whatothertroopsintheworldaresoindependent？Withthesunfortheirguide，mare’sfleshforfood，theirsaddle-clothsforbeds，——aslongasthereisalittlewater，thesemenwouldpenetratetotheendoftheworld。
AfewdaysafterwardsIsawanothertroopofthesebanditti-likesoldiersstartonanexpeditionagainstatribeofIndiansatthesmallSalinas，whohadbeenbetrayedbyaprisonercacique。TheSpaniardwhobroughttheordersforthisexpeditionwasaveryintelligentman。Hegavemeanaccountofthelastengagementatwhichhewaspresent。SomeIndians，whohadbeentakenprisoners，gaveinformationofatribelivingnorthoftheColorado。