so　as　to　prevent　their　becoming　excessively　limp　when　exposed　at
  night　to　rain　and　dew。　　The　sides　of　all　the　triangles　were　three
  inches　in　length；　with　the　bases　of　120　one　inch；　and　of　the　other
  183　half　an　inch　in　length。　　These　latter　triangles　were　very
  narrow　or　much　acuminated。　｛32｝　　As　a　check　on　the　observations
  presently　to　be　given；　similar　triangles　in　a　damp　state　were
  seized　by　a　very　narrow　pair　of　pincers　at　different　points　and　at
  all　inclinations　with　reference　to　the　margins；　and　were　then　drawn
  into　a　short　tube　of　the　diameter　of　a　worm…burrow。　　If　seized　by
  the　apex；　the　triangle　was　drawn　straight　into　the　tube；　with　its
  margins　infolded；　if　seized　at　some　little　distance　from　the　apex；
  for　instance　at　half　an　inch；　this　much　was　doubled　back　within　the
  tube。　　So　it　was　with　the　base　and　basal　angles；　though　in　this
  case　the　triangles　offered；　as　might　have　been　expected；　much　more
  resistance　to　being　drawn　in。　　If　seized　near　the　middle　the
  triangle　was　doubled　up；　with　the　apex　and　base　left　sticking　out
  of　the　tube。　　As　the　sides　of　the　triangles　were　three　inches　in
  length；　the　result　of　their　being　drawn　into　a　tube　or　into　a
  burrow　in　different　ways；　may　be　conveniently　divided　into　three
  groups：　　those　drawn　in　by　the　apex　or　within　an　inch　of　it；　those
  drawn　in　by　the　base　or　within　an　inch　of　it；　and　those　drawn　in　by
  any　point　in　the　middle　inch。
  In　order　to　see　how　the　triangles　would　be　seized　by　worms；　some　in
  a　damp　state　were　given　to　worms　kept　in　confinement。　　They　were
  seized　in　three　different　manners　in　the　case　of　both　the　narrow
  and　broad　triangles：　　viz。；　by　the　margin；　by　one　of　the　three
  angles；　which　was　often　completely　engulfed　in　their　mouths；　and
  lastly；　by　suction　applied　to　any　part　of　the　flat　surface。　　If
  lines　parallel　to　the　base　and　an　inch　apart；　are　drawn　across　a
  triangle　with　the　sides　three　inches　in　length；　it　will　be　divided
  into　three　parts　of　equal　length。　　Now　if　worms　seized
  indifferently　by　chance　any　part；　they　would　assuredly　seize　on　the
  basal　part　or　division　far　oftener　than　on　either　of　the　two　other
  divisions。　　For　the　area　of　the　basal　to　the　apical　part　is　as　5　to
  1；　so　that　the　chance　of　the　former　being　drawn　into　a　burrow　by
  suction；　will　be　as　5　to　1；　compared　with　the　apical　part。　　The
  base　offers　two　angles　and　the　apex　only　one；　so　that　the　former
  would　have　twice　as　good　a　chance　（independently　of　the　size　of　the
  angles）　of　being　engulfed　in　a　worm's　mouth；　as　would　the　apex。　　It
  should；　however；　be　stated　that　the　apical　angle　is　not　often
  seized　by　worms；　the　margin　at　a　little　distance　on　either　side
  being　preferred。　　I　judge　of　this　from　having　found　in　40　out　of　46
  cases　in　which　triangles　had　been　drawn　into　burrows　by　their
  apical　ends；　that　the　tip　had　been　doubled　back　within　the　burrow
  for　a　length　of　between　1/20　of　an　inch　and　1　inch。　　Lastly；　the
  proportion　between　the　margins　of　the　basal　and　apical　parts　is　as
  3　to　2　for　the　broad；　and　2。5　to　2　for　the　narrow　triangles。　　From
  these　several　considerations　it　might　certainly　have　been　expected；
  supposing　that　worms　seized　hold　of　the　triangles　by　chance；　that　a
  considerably　larger　proportion　would　have　been　dragged　into　the
  burrows　by　the　basal　than　by　the　apical　part；　but　we　shall
  immediately　see　how　different　was　the　result。
  Triangles　of　the　above　specified　sizes　were　scattered　on　the　ground
  in　many　places　and　on　many　successive　nights　near　worm…burrows；
  from　which　the　leaves；　petioles；　twigs；　&c。；　with　which　they　had
  been　plugged；　were　removed。　　Altogether　303　triangles　were　drawn　by
  worms　into　their　burrows：　　12　others　were　drawn　in　by　both　ends；
  but　as　it　was　impossible　to　judge　by　which　end　they　had　been　first
  seized；　these　are　excluded。　　Of　the　303；　62　per　cent。　had　been
  drawn　in　by　the　apex　（using　this　term　for　all　drawn　in　by　the
  apical　part；　one　inch　in　length）；　15　per　cent。　by　the　middle；　and
  23　per　cent。　by　the　basal　part。　　If　they　had　been　drawn
  indifferently　by　any　point；　the　proportion　for　the　apical；　middle
  and　basal　parts　would　have　been　33。3　per　cent。　for　each；　but；　as　we
  have　just　seen；　it　might　have　been　expected　that　a　much　larger
  proportion　would　have　been　drawn　in　by　the　basal　than　by　any　other
  part。　　As　the　case　stands；　nearly　three　times　as　many　were　drawn　in
  by　the　apex　as　by　the　base。　　If　we　consider　the　broad　triangles　by
  themselves；　59　per　cent。　were　drawn　in　by　the　apex；　25　per　cent。　by
  the　middle；　and　16　per　cent。　by　the　base。　　Of　the　narrow　triangles；
  65　per　cent。　were　drawn　in　by　the　apex；　14　per　cent；　by　the　middle；
  and　21　per　cent。　by　the　base；　so　that　here　those　drawn　in　by　the
  apex　were　more　than　3　times　as　many　as　those　drawn　in　by　the　base。
  We　may　therefore　conclude　that　the　manner　in　which　the　triangles
  are　drawn　into　the　burrows　is　not　a　matter　of　chance。
  In　eight　cases；　two　triangles　had　been　drawn　into　the　same　burrow；
  and　in　seven　of　these　cases；　one　had　been　drawn　in　by　the　apex　and
  the　other　by　the　base。　　This　again　indicates　that　the　result　is　not
  determined　by　chance。　　Worms　appear　sometimes　to　revolve　in　the　act
  of　drawing　in　the　triangles；　for　five　out　of　the　whole　lot　had　been
  wound　into　an　irregular　spire　round　the　inside　of　the　burrow。
  Worms　kept　in　a　warm　room　drew　63　triangles　into　their　burrows；
  but；　as　in　the　case　of　the　pine…leaves；　they　worked　in　a　rather
  careless　manner；　for　only　44　per　cent。　were　drawn　in　by　the　apex；
  22　per　cent。　by　the　middle；　and　33　per　cent。　by　the　base。　　In　five
  cases；　two　triangles　were　drawn　into　the　same　burrow。
  It　may　be　suggested　with　much　apparent　probability　that　so　large　a
  proportion　of　the　triangles　were　drawn　in　by　the　apex；　not　from　the
  worms　having　selected　this　end　as　the　most　convenient　for　the
  purpose；　but　from　having　first　tried　in　other　ways　and　failed。
  This　notion　was　countenanced　by　the　manner　in　which　worms　in
  confinement　were　seen　to　drag　about　and　drop　the　triangles；　but
  then　they　were　working　carelessly。　　I　did　not　at　first　perceive　the
  importance　of　this　subject；　but　merely　noticed　that　the　bases　of
  those　triangles　which　had　been　drawn　in　by　the　apex；　were　generally
  clean　and　not　crumpled。　　The　subject　was　afterwards　attended　to
  carefully。　　In　the　first　place　several　triangles　which　had　been
  drawn　in　by　the　basal　angles；　or　by　the　base；　or　a　little　above　the
  base；　and　which　were　thus　much　crumpled　and　dirtied；　were　left　for
  some　hours　in　water　and　were　then　well　shaken　while　immersed；　but
  neither　the　dirt　nor　the　creases　were　thus　removed。　　Only　slight
  creases　could　be　obliterated；　even　by　pulling　the　wet　triangles
  several　times　through　my　fingers。　　Owing　to　the　slime　from　the
  worms'　bodies；　the　dirt　was　not　easily　washed　off。　　We　may
  therefore　conclude　that　if　a　triangle；　before　being　dragged　in　by
  the　apex；　had　been　dragged　into　a　burrow　by　its　base　with　even　a
  slight　degree　of　force；　the　basal　part　would　long　retain　its
  creases　and　remain　dirty。　　The　condition　of　89　triangles　（65　narrow
  and　24　broad　ones）；　which　had　been　drawn　in　by　the　apex；　was
  observed；　and　the　bases　of　only　7　of　them　were　at　all　creased；
  being　at　the　same　time　generally　dirty。　　Of　the　82　uncreased
  triangles；　14　were　dirty　at　the　base；　but　it　does　not　follow　from
  this　fact　that　these　had　first　been　dragged　towards　the　burrows　by
  their　bases；　for　the　worms　sometimes　covered　large　portions　of　the
  triangles　with　slime；　and　these　when　dragged　by　the　apex　over　the
  ground　would　be　dirtied；　and　during　rainy　weather；　the　triangles
  were　often　dirtied　over　one　whole　side　or　over　both　sides。　　If　the
  worms　had　dragged　the　triangles　to　the　mouths　of　their　burrows　by
  their　bases；　as　often　as　by　their　apices；　and　had　then　perceived；
  without　actually　trying　to　draw　them　into　the　burrow；　that　the
  broader　end　was　not　well　adapted　for　this　purposeeven　in　this
  case　a　large　proportion　would　probably　have　had　their　basal　ends
  dirtied。　　We　may　therefore　inferimprobable　as　is　the　inference
  that　worms　are　able　by　some　means　to　judge　which　is　the　best　end　by
  which　to　draw　triangles　of　paper　into　their　burrows。
  The　percentage　results　of　the　foregoing　observations　on　the　manner
  in　which　worms　draw　various　kinds　of　objects　into　the　mouths　of
  their　burrows　may　be　abridged　as　follows：…
  Drawn
  into　the　　　　Drawn　in；　Drawn　in；
  Nature　of　Object。　　　　　　　　　　　　burrows；　　　　by　or　　　　　by　or
  by　or　　　　　　　near　　　　　　near
  near　the　　　　the　　　　　　　the
  apex。　　　　　　　middle。　　　base。
  Leaves　of　various　kinds　　　　　　　　　　80　　　　　　　　11　　　　　　　　　9
  …　of　the　Lime；　basal　margin
  of　blade　broad；　apex
  acuminated　　　　　　　　　　　　　　　　　　　　　79　　　　　　　　17　　　　　　　　　4
  …　of　a　Laburnum；　basal　part　of
  blade　as　narrow　as；　or　some…
  times　little　narrower　than
  the　apical　part　　　　　　　　　　　　　　　　63　　　　　　　　10　　　　　　　　27
  …　of　the　Rhododendron；　basal
  part　of　blade　often　narrower
  than　the　apical　part　　　　　　　　　　　34　　　　　　　。。。　　　　　　　　66
  …　of　Pine…trees；　consisting　of
  two　needles