burrows　are　not　gnawed。　　I　have　seen　as　many　as　nine　leaves　of　the
  lime…tree　drawn　into　the　same　burrow；　and　not　nearly　all　of　them
  had　been　gnawed；　but　such　leaves　may　serve　as　a　store　for　future
  consumption。　　Where　fallen　leaves　are　abundant；　many　more　are
  sometimes　collected　over　the　mouth　of　a　burrow　than　can　be　used；　so
  that　a　small　pile　of　unused　leaves　is　left　like　a　roof　over　those
  which　have　been　partly　dragged　in。
  A　leaf　in　being　dragged　a　little　way　into　a　cylindrical　burrow　is
  necessarily　much　folded　or　crumpled。　　When　another　leaf　is　drawn
  in；　this　is　done　exteriorly　to　the　first　one；　and　so　on　with　the
  succeeding　leaves；　and　finally　all　become　closely　folded　and
  pressed　together。　　Sometimes　the　worm　enlarges　the　mouth　of　its
  burrow；　or　makes　a　fresh　one　close　by；　so　as　to　draw　in　a　still
  larger　number　of　leaves。　　They　often　or　generally　fill　up　the
  interstices　between　the　drawn…in　leaves　with　moist　viscid　earth
  ejected　from　their　bodies；　and　thus　the　mouths　of　the　burrows　are
  securely　plugged。　　Hundreds　of　such　plugged　burrows　may　be　seen　in
  many　places；　especially　during　the　autumnal　and　early　winter
  months。　　But；　as　will　hereafter　be　shown；　leaves　are　dragged　into
  the　burrows　not　only　for　plugging　them　up　and　for　food；　but　for　the
  sake　of　lining　the　upper　part　or　mouth。
  When　worms　cannot　obtain　leaves；　petioles；　sticks；　&c。；　with　which
  to　plug　up　the　mouths　of　their　burrows；　they　often　protect　them　by
  little　heaps　of　stones；　and　such　heaps　of　smooth　rounded　pebbles
  may　frequently　be　seen　on　gravel…walks。　　Here　there　can　be　no
  question　about　food。　　A　lady；　who　was　interested　in　the　habits　of
  worms；　removed　the　little　heaps　of　stones　from　the　mouths　of
  several　burrows　and　cleared　the　surface　of　the　ground　for　some
  inches　all　round。　　She　went　out　on　the　following　night　with　a
  lantern；　and　saw　the　worms　with　their　tails　fixed　in　their　burrows；
  dragging　the　stones　inwards　by　the　aid　of　their　mouths；　no　doubt　by
  suction。　　〃After　two　nights　some　of　the　holes　had　8　or　9　small
  stones　over　them；　after　four　nights　one　had　about　30；　and　another
  34　stones。〃　｛29｝　　One　stonewhich　had　been　dragged　over　the
  gravel…walk　to　the　mouth　of　a　burrow　weighed　two　ounces；　and　this
  proves　how　strong　worms　are。　　But　they　show　greater　strength　in
  sometimes　displacing　stones　in　a　well…trodden　gravel…walk；　that
  they　do　so；　may　be　inferred　from　the　cavities　left　by　the　displaced
  stones　being　exactly　filled　by　those　lying　over　the　mouths　of
  adjoining　burrows；　as　I　have　myself　observed。
  Work　of　this　kind　is　usually　performed　during　the　night；　but　I　have
  occasionally　known　objects　to　be　drawn　into　the　burrows　during　the
  day。　　What　advantage　the　worms　derive　from　plugging　up　the　mouths
  of　their　burrows　with　leaves；　&c。；　or　from　piling　stones　over　them；
  is　doubtful。　　They　do　not　act　in　this　manner　at　the　times　when　they
  eject　much　earth　from　their　burrows；　for　their　castings　then　serve
  to　cover　the　mouths。　　When　gardeners　wish　to　kill　worms　on　a　lawn；
  it　is　necessary　first　to　brush　or　rake　away　the　castings　from　the
  surface；　in　order　that　the　lime…water　may　enter　the　burrows。　｛30｝
  It　might　be　inferred　from　this　fact　that　the　mouths　are　plugged　up
  with　leaves；　&c。；　to　prevent　the　entrance　of　water　during　heavy
  rain；　but　it　may　be　urged　against　this　view　that　a　few；　loose；
  well…rounded　stones　are　ill…adapted　to　keep　out　water。　　I　have
  moreover　seen　many　burrows　in　the　perpendicularly　cut　turf…edgings
  to　gravel…walks；　into　which　water　could　hardly　flow；　as　well
  plugged　as　burrows　on　a　level　surface。　　It　is　not　probable　that　the
  plugs　or　piles　of　stones　serve　to　conceal　the　burrows　from
  scolopendras；　which；　according　to　Hoffmeister；　｛31｝　are　the
  bitterest　enemies　of　worms；　or　from　the　larger　species　of　Carabus
  and　Staphylinus　which　attack　them　ferociously；　for　these　animals
  are　nocturnal；　and　the　burrows　are　opened　at　night。　　May　not　worms
  when　the　mouth　of　the　burrow　is　protected　be　able　to　remain　with
  safety　with　their　heads　close　to　it；　which　we　know　that　they　like
  to　do；　but　which　costs　so　many　of　them　their　lives？　　Or　may　not　the
  plugs　check　the　free　ingress　of　the　lowest　stratum　of　air；　when
  chilled　by　radiation　at　night；　from　the　surrounding　ground　and
  herbage？　　I　am　inclined　to　believe　in　this　latter　view：　　firstly；
  because　when　worms　were　kept　in　pots　in　a　room　with　a　fire；　in
  which　case　cold　air　could　not　enter　the　burrows；　they　plugged　them
  up　in　a　slovenly　manner；　and　secondarily；　because　they　often　coat
  the　upper　part　of　their　burrows　with　leaves；　apparently　to　prevent
  their　bodies　from　coming　into　close　contact　with　the　cold　damp
  earth。　　Mr。　E。　Parfitt　has　suggested　to　me　that　the　mouths　of　the
  burrows　are　closed　in　order　that　the　air　within　them　may　be　kept
  thoroughly　damp；　and　this　seems　the　most　probable　explanation　of
  the　habit。　　But　the　plugging…up　process　may　serve　for　all　the　above
  purposes。
  Whatever　the　motive　may　be；　it　appears　that　worms　much　dislike
  leaving　the　mouths　of　their　burrows　open。　　Nevertheless　they　will
  reopen　them　at　night；　whether　or　not　they　can　afterwards　close
  them。　　Numerous　open　burrows　may　be　seen　on　recently…dug　ground；
  for　in　this　case　the　worms　eject　their　castings　in　cavities　left　in
  the　ground；　or　in　the　old　burrows　instead　of　piling　them　over　the
  mouths　of　their　burrows；　and　they　cannot　collect　objects　on　the
  surface　by　which　the　mouths　might　be　protected。　　So　again　on　a
  recently　disinterred　pavement　of　a　Roman　villa　at　Abinger
  （hereafter　to　be　described）　the　worms　pertinaciously　opened　their
  burrows　almost　every　night；　when　these　had　been　closed　by　being
  trampled　on；　although　they　were　rarely　able　to　find　a　few　minute
  stones　wherewith　to　protect　them。
  Intelligence　shown　by　worms　in　their　manner　of　plugging　up　their
  burrows。If　a　man　had　to　plug　up　a　small　cylindrical　hole；　with
  such　objects　as　leaves；　petioles　or　twigs；　he　would　drag　or　push
  them　in　by　their　pointed　ends；　but　if　these　objects　were　very　thin
  relatively　to　the　size　of　the　hole；　he　would　probably　insert　some
  by　their　thicker　or　broader　ends。　　The　guide　in　his　case　would　be
  intelligence。　　It　seemed　therefore　worth　while　to　observe　carefully
  how　worms　dragged　leaves　into　their　burrows；　whether　by　their　tips
  or　bases　or　middle　parts。　　It　seemed　more　especially　desirable　to
  do　this　in　the　case　of　plants　not　natives　to　our　country；　for
  although　the　habit　of　dragging　leaves　into　their　burrows　is
  undoubtedly　instinctive　with　worms；　yet　instinct　could　not　tell
  them　how　to　act　in　the　case　of　leaves　about　which　their　progenitors
  knew　nothing。　　If；　moreover；　worms　acted　solely　through　instinct　or
  an　unvarying　inherited　impulse；　they　would　draw　all　kinds　of　leaves
  into　their　burrows　in　the　same　manner。　　If　they　have　no　such
  definite　instinct；　we　might　expect　that　chance　would　determine
  whether　the　tip；　base　or　middle　was　seized。　　If　both　these
  alternatives　are　excluded；　intelligence　alone　is　left；　unless　the
  worm　in　each　case　first　tries　many　different　methods；　and　follows
  that　alone　which　proves　possible　or　the　most　easy；　but　to　act　in
  this　manner　and　to　try　different　methods　makes　a　near　approach　to
  intelligence。
  In　the　first　place　227　withered　leaves　of　various　kinds；　mostly　of
  English　plants；　were　pulled　out　of　worm…burrows　in　several　places。
  Of　these；　181　had　been　drawn　into　the　burrows　by　or　near　their
  tips；　so　that　the　foot…stalk　projected　nearly　upright　from　the
  mouth　of　the　burrow；　20　had　been　drawn　in　by　their　bases；　and　in
  this　case　the　tips　projected　from　the　burrows；　and　26　had　been
  seized　near　the　middle；　so　that　these　had　been　drawn　in
  transversely　and　were　much　crumpled。　　Therefore　80　per　cent。
  （always　using　the　nearest　whole　number）　had　been　drawn　in　by　the
  tip；　9　per　cent。　by　the　base　or　foot…stalk；　and　11　per　cent。
  transversely　or　by　the　middle。　　This　alone　is　almost　sufficient　to
  show　that　chance　does　not　determine　the　manner　in　which　leaves　are
  dragged　into　the　burrows。
  Of　the　above　227　leaves；　70　consisted　of　the　fallen　leaves　of　the
  common　lime…tree；　which　is　almost　certainly　not　a　native　of
  England。　　These　leaves　are　much　acuminated　towards　the　tip；　and　are
  very　broad　at　the　base　with　a　well…developed　foot…stalk。　　They　are
  thin　and　quite　flexible　when　half…withered。　　Of　the　70；　79　per
  cent。　had　been　drawn　in　by　or　near　the　tip；　4　per　cent。　by　or　near
  the　base；　and　17　per　cent。　transversely　or　by　the　middle。　　These
  proportions　agree　very　closely；　as　far　as　the　tip　is　concerned；
  with　those　before　given。　　But　the　percentage　drawn　in　by　the　base
  is　smaller；　which　may　be　attributed　to　the　breadth　of　the　basal
  part　of　the　blade。　　We　here；　also；　see　that　the　presence　of　a　foot…
  stalk；　which　it　might　have　been　expected　would　have　tempted　the
  worms　as　a　convenient　handle；　has　little　or　no　influence　in
  determining　the　manner　in　which　lime　leaves　are　dragged　into　the
  burrows。　　The　considerable　proportion；　viz。；　17　per　cent。；　drawn　in
  more　or　less　transversely　depends　no　doubt　on　the　flexibility　of
  these　half…decayed　leaves。　　The　fact　of　so　many　having　been　drawn