part　of　blade　often　narrower
  than　the　apical　part　　　　　　　　　　　34　　　　　　　。。。　　　　　　　　66
  …　of　Pine…trees；　consisting　of
  two　needles　arising　from　a
  common　base　　　　　　　　　　　　　　　　　　　　。。。　　　　　　。。。　　　　　　　100
  Petioles　of　a　Clematis；
  somewhat　pointed　at　the　apex；
  and　blunt　at　the　base　　　　　　　　　　76　　　　　　　。。。　　　　　　　　24
  …　of　the　Ash；　the　thick　basal
  end　often　drawn　in　to　serve
  as　food　　　　　　　　　　　　　　　　　　　　　　　48。5　　　　　　。。。　　　　　　51。5
  …　of　Robinia；　extremely　thin；
  especially　towards　the　apex；
  so　as　to　be　ill…fitted　for
  plugging　up　the　burrows　　　　　　　　44　　　　　　。。。　　　　　　　　56
  Triangles　of　paper；　of　the
  two　sizes　　　　　　　　　　　　　　　　　　　　　　62　　　　　　　15　　　　　　　　23
  …　of　the　broad　ones　alone　　　　　　　　59　　　　　　　25　　　　　　　　16
  …　of　the　narrow　ones　alone　　　　　　　65　　　　　　　14　　　　　　　　21
  If　we　consider　these　several　　cases；　we　can　hardly　escape　from　the
  conclusion　that　worms　show　some　degree　of　intelligence　in　their
  manner　of　plugging　up　their　burrows。　　Each　particular　object　is
  seized　in　too　uniform　a　manner；　and　from　causes　which　we　can
  generally　understand；　for　the　result　to　be　attributed　to　mere
  chance。　　That　every　object　has　not　been　drawn　in　by　its　pointed
  end；　may　be　accounted　for　by　labour　having　been　saved　through　some
  being　inserted　by　their　broader　or　thicker　ends。　　No　doubt　worms
  are　led　by　instinct　to　plug　up　their　burrows；　and　it　might　have
  been　expected　that　they　would　have　been　led　by　instinct　how　best　to
  act　in　each　particular　case；　independently　of　intelligence。　　We　see
  how　difficult　it　is　to　judge　whether　intelligence　comes　into　play；
  for　even　plants　might　sometimes　be　thought　to　be　thus　directed；　for
  instance　when　displaced　leaves　re…direct　their　upper　surfaces
  towards　the　light　by　extremely　complicated　movements　and　by　the
  shortest　course。　　With　animals；　actions　appearing　due　to
  intelligence　may　be　performed　through　inherited　habit　without　any
  intelligence；　although　aboriginally　thus　acquired。　　Or　the　habit
  may　have　been　acquired　through　the　preservation　and　inheritance　of
  beneficial　variations　of　some　other　habit；　and　in　this　case　the　new
  habit　will　have　been　acquired　independently　of　intelligence
  throughout　the　whole　course　of　its　development。　　There　is　no　a
  priori　improbability　in　worms　having　acquired　special　instincts
  through　either　of　these　two　latter　means。　　Nevertheless　it　is
  incredible　that　instincts　should　have　been　developed　in　reference
  to　objects；　such　as　the　leaves　of　petioles　of　foreign　plants；
  wholly　unknown　to　the　progenitors　of　the　worms　which　act　in　the
  described　manner。　　Nor　are　their　actions　so　unvarying　or　inevitable
  as　are　most　true　instincts。
  As　worms　are　not　guided　by　special　instincts　in　each　particular
  case；　though　possessing　a　general　instinct　to　plug　up　their
  burrows；　and　as　chance　is　excluded；　the　next　most　probable
  conclusion　seems　to　be　that　they　try　in　many　different　ways　to　draw
  in　objects；　and　at　last　succeed　in　some　one　way。　　But　it　is
  surprising　that　an　animal　so　low　in　the　scale　as　a　worm　should　have
  the　capacity　for　acting　in　this　manner；　as　many　higher　animals　have
  no　such　capacity。　　For　instance；　ants　may　be　seen　vainly　trying　to
  drag　an　object　transversely　to　their　course；　which　could　be　easily
  drawn　longitudinally；　though　after　a　time　they　generally　act　in　a
  wiser　manner；　M。　Fabre　states　｛33｝　that　a　Sphexan　insect
  belonging　to　the　same　highly…endowed　order　with　antsstocks　its
  nest　with　paralysed　grass…hoppers；　which　are　invariably　dragged
  into　the　burrow　by　their　antennae。　　When　these　were　cut　off　close
  to　the　head；　the　Sphex　seized　the　palpi；　but　when　these　were
  likewise　cut　off；　the　attempt　to　drag　its　prey　into　the　burrow　was
  given　up　in　despair。　　The　Sphex　had　not　intelligence　enough　to
  seize　one　of　the　six　legs　or　the　ovipositor　of　the　grasshopper；
  which；　as　M。　Fabre　remarks；　would　have　served　equally　well。　　So
  again；　if　the　paralysed　prey　with　an　egg　attached　to　it　be　taken
  out　of　the　cell；　the　Sphex　after　entering　and　finding　the　cell
  empty；　nevertheless　closes　it　up　in　the　usual　elaborate　manner。
  Bees　will　try　to　escape　and　go　on　buzzing　for　hours　on　a　window；
  one　half　of　which　has　been　left　open。　　Even　a　pike　continued　during
  three　months　to　dash　and　bruise　itself　against　the　glass　sides　of
  an　aquarium；　in　the　vain　attempt　to　seize　minnows　on　the　opposite
  side。　｛34｝　　A　cobra…snake　was　seen　by　Mr。　Layard　｛35｝　to　act　much
  more　wisely　than　either　the　pike　or　the　Sphex；　it　had　swallowed　a
  toad　lying　within　a　hole；　and　could　not　withdraw　its　head；　the　toad
  was　disgorged；　and　began　to　crawl　away；　it　was　again　swallowed　and
  again　disgorged；　and　now　the　snake　had　learnt　by　experience；　for　it
  seized　the　toad　by　one　of　its　legs　and　drew　it　out　of　the　hole。
  The　instincts　of　even　the　higher　animals　are　often　followed　in　a
  senseless　or　purposeless　manner：　　the　weaver…bird　will
  perseveringly　wind　threads　through　the　bars　of　its　cage；　as　if
  building　a　nest：　　a　squirrel　will　pat　nuts　on　a　wooden　floor；　as　if
  he　had　just　buried　them　in　the　ground：　　a　beaver　will　cut　up　logs
  of　wood　and　drag　them　about；　though　there　is　no　water　to　dam　up；
  and　so　in　many　other　cases。
  Mr。　Romanes；　who　has　specially　studied　the　minds　of　animals；
  believes　that　we　can　safely　infer　intelligence；　only　when　we　see　an
  individual　profiting　by　its　own　experience。　　By　this　test　the　cobra
  showed　some　intelligence；　but　this　would　have　been　much　plainer　if
  on　a　second　occasion　he　had　drawn　a　toad　out　of　a　hole　by　its　leg。
  The　Sphex　failed　signally　in　this　respect。　　Now　if　worms　try　to
  drag　objects　into　their　burrows　first　in　one　way　and　then　in
  another；　until　they　at　last　succeed；　they　profit；　at　least　in　each
  particular　instance；　by　experience。
  But　evidence　has　been　advanced　showing　that　worms　do　not　habitually
  try　to　draw　objects　into　their　burrows　in　many　different　ways。
  Thus　half…decayed　lime…leaves　from　their　flexibility　could　have
  been　drawn　in　by　their　middle　or　basal　parts；　and　were　thus　drawn
  into　the　burrows　in　considerable　numbers；　yet　a　large　majority　were
  drawn　in　by　or　near　the　apex。　　The　petioles　of　the　Clematis　could
  certainly　have　been　drawn　in　with　equal　ease　by　the　base　and　apex；
  yet　three　times　and　in　certain　cases　five　times　as　many　were　drawn
  in　by　the　apex　as　by　the　base。　　It　might　have　been　thought　that　the
  foot…stalks　of　leaves　would　have　tempted　the　worms　as　a　convenient
  handle；　yet　they　are　not　largely　used；　except　when　the　base　of　the
  blade　is　narrower　than　the　apex。　　A　large　number　of　the　petioles　of
  the　ash　are　drawn　in　by　the　base；　but　this　part　serves　the　worms　as
  food。　　In　the　case　of　pine…leaves　worms　plainly　show　that　they　at
  least　do　not　seize　the　leaf　by　chance；　but　their　choice　does　not
  appear　to　be　determined　by　the　divergence　of　the　two　needles；　and
  the　consequent　advantage　or　necessity　of　drawing　them　into　their
  burrows　by　the　base。　　With　respect　to　the　triangles　of　paper；　those
  which　had　been　drawn　in　by　the　apex　rarely　had　their　bases　creased
  or　dirty；　and　this　shows　that　the　worms　had　not　often　first　tried
  to　drag　them　in　by　this　end。
  If　worms　are　able　to　judge；　either　before　drawing　or　after　having
  drawn　an　object　close　to　the　mouths　of　their　burrows；　how　best　to
  drag　it　in；　they　must　acquire　some　notion　of　its　general　shape。
  This　they　probably　acquire　by　touching　it　in　many　places　with　the
  anterior　extremity　of　their　bodies；　which　serves　as　a　tactile
  organ。　　It　may　be　well　to　remember　how　perfect　the　sense　of　touch
  becomes　in　a　man　when　born　blind　and　deaf；　as　are　worms。　　If　worms
  have　the　power　of　acquiring　some　notion；　however　rude；　of　the　shape
  of　an　object　and　of　their　burrows；　as　seems　to　be　the　case；　they
  deserve　to　be　called　intelligent；　for　they　then　act　in　nearly　the
  same　manner　as　would　a　man　under　similar　circumstances。
  To　sum　up；　as　chance　does　not　determine　the　manner　in　which　objects
  are　drawn　into　the　burrows；　and　as　the　existence　of　specialized
  instincts　for　each　particular　case　cannot　be　admitted；　the　first
  and　most　natural　supposition　is　that　worms　try　all　methods　until
  they　at　last　succeed；　but　many　appearances　are　opposed　to　such　a
  supposition。　　One　alternative　alone　is　left；　namely；　that　worms；
  although　standing　low　in　the　scale　of　organization；　possess　some
  degree　of　intelligence。　　This　will　strike　every　one　as　very
  improbable；　but　it　may　be　doubted　whether　we　know　enough　about　the
  nervous　system　of　the　lower　animals　to　justify　our　natural　distrust
  of　such　a　conclusion。　　With　respect　to　the　small　size　of　the
  cerebral　ganglia；　we　should　remember　what　a　mass　of　inherited
  knowledge；　with　some　power　of　adapting　means　to　an　end；　is　crowded
  into　the　minute　brain　of　a　worker…ant。
  Means　by　which　worms　excavate　their　burrows。This　is　effected　in
  two　ways；　by　pushing　away　the　earth　on　all　sides；　and　by　swallowing
  it。　　In　the　former　case；　the　worm　inserts　the　stretched　out　and
  attenuated　anterior　extremity　of　its　body　into　any　little　crevice；
  or　hole；　and　then；　as　Perrier　remarks；　｛36｝　the　pharynx　is　pushed
  forwards　into　this　part；　which　consequently　swells　and　pushes　away
  the　earth　on　all　sides。　　The　ant