﻿ACADEMY 
  OF 
  SCIENCES. 
  405 
  

  

  fflents, 
  is 
  by 
  looi^ing 
  the 
  body 
  in 
  a 
  manner 
  precisely 
  similar 
  to 
  that 
  practiced 
  by 
  

   the 
  " 
  loopers," 
  or 
  larvae 
  of 
  the 
  Geometridcc. 
  

  

  The 
  first 
  pair 
  of 
  legs' 
  is 
  short, 
  but 
  the 
  second 
  makes 
  up 
  by 
  its 
  inordinate 
  

   length 
  and 
  slenderuess 
  ; 
  while 
  the 
  three 
  hinder 
  pairs 
  are 
  more 
  nearly 
  equal 
  in 
  size, 
  

   and 
  are 
  known 
  as 
  " 
  anchoral 
  " 
  feet, 
  since 
  it 
  is 
  by 
  them 
  that 
  the 
  creature 
  attaches 
  

   itself 
  firmly 
  to 
  the 
  object 
  on 
  which 
  it 
  rests. 
  

  

  All 
  the 
  feet 
  are 
  provided 
  with 
  sharp 
  claws, 
  which 
  fold 
  back 
  upon 
  the 
  preced- 
  

   ing 
  joint 
  ; 
  but 
  in 
  the 
  last 
  three 
  pairs 
  this 
  joint 
  is 
  furnished 
  with 
  a 
  sharp 
  spine, 
  

   against 
  which 
  the 
  claw 
  shuts. 
  Thus 
  our 
  Caprella, 
  secured 
  by 
  six 
  anchors, 
  can 
  ride 
  

   safely 
  in 
  spite 
  of 
  waves 
  and 
  currents, 
  its 
  long 
  body 
  swaying 
  to 
  and 
  fro, 
  and 
  its 
  

   forelegs 
  busy 
  in 
  catching 
  its 
  prey. 
  The 
  Caprellce 
  appear 
  to 
  be 
  parasitic 
  on 
  

   hydroids 
  and 
  sponges. 
  

  

  The 
  species 
  of 
  which 
  I 
  append 
  a 
  technical 
  description 
  was 
  dredged 
  in 
  about 
  

   eight 
  fathoms 
  of 
  water, 
  from 
  a 
  bottom 
  of 
  mud 
  and 
  wee(^, 
  in 
  Hakodadi 
  Bay, 
  

   Japan, 
  by 
  W. 
  J. 
  Fisher, 
  naturalist 
  of 
  the 
  Tuscarora. 
  Mr. 
  Fisher 
  has 
  present- 
  

   ed 
  two 
  specimens, 
  male 
  and 
  female, 
  to 
  this 
  Academy. 
  

  

  I 
  believe 
  the 
  species 
  to 
  be 
  new, 
  although 
  it 
  is 
  just 
  possible 
  that 
  it 
  may 
  have 
  

   been 
  previously 
  described 
  by 
  some 
  naturalist 
  whose 
  works 
  do 
  not 
  grace 
  the 
  

   shelves 
  of 
  our 
  Academy. 
  I 
  have 
  named 
  it 
  C. 
  spinosa. 
  The 
  male 
  somewhat 
  re- 
  

   sembles 
  the 
  C. 
  attemtata 
  of 
  Dana, 
  the 
  chief 
  differences-being 
  the 
  spines 
  upon 
  

   the 
  five 
  posterior 
  segments, 
  and 
  the 
  absence 
  of 
  the 
  spine 
  upon 
  the 
  head. 
  

  

  The 
  females 
  differ 
  so 
  greatly 
  from 
  the 
  males 
  in 
  the 
  comparative 
  lengths 
  of 
  the 
  

   several 
  joints 
  of 
  the 
  body 
  and 
  antenna, 
  that 
  I 
  was 
  at 
  first 
  inclined 
  to 
  believe 
  

   they 
  belonged 
  to 
  another 
  species 
  ; 
  but 
  since 
  the 
  two 
  forms 
  were 
  always 
  dredged 
  

   in 
  company, 
  and 
  the 
  specimens 
  of 
  one 
  form 
  are 
  all 
  males, 
  while 
  those 
  of 
  the 
  

   other 
  are 
  all 
  females, 
  it 
  is 
  evident 
  that 
  they 
  are 
  the 
  two 
  sexes 
  of 
  the 
  same 
  

   species. 
  

  

  Caprella 
  spinosa. 
  Lockington. 
  

  

  Male. 
  Body 
  very 
  slender 
  ; 
  segments 
  elongate, 
  second 
  thoracic 
  segment 
  more 
  

   than 
  one-half 
  longer 
  than 
  the 
  first, 
  and 
  very 
  slender. 
  No 
  spine 
  on 
  dorsal 
  sur- 
  

   face 
  of 
  head. 
  Superior 
  antennas 
  longer 
  than 
  half 
  the 
  body 
  ; 
  first 
  joint 
  little 
  

   more 
  than 
  half 
  the 
  length 
  of 
  second 
  ; 
  third 
  joint 
  nearly 
  as 
  long 
  as 
  second 
  ; 
  

   flagellum 
  rather 
  longer 
  than 
  basal 
  joint. 
  Inferior 
  antennae 
  reaching 
  to 
  about 
  

   the 
  first 
  third 
  of 
  the 
  second 
  joint 
  of 
  the 
  superior 
  antennae. 
  Hand 
  of 
  second 
  pair 
  

   of 
  legs 
  very 
  narrow, 
  with 
  three 
  teeth 
  on 
  the 
  underside, 
  one 
  a 
  short 
  distance 
  be- 
  

   hind 
  the 
  claw, 
  a 
  second 
  close 
  to 
  the 
  first, 
  and 
  a 
  third 
  posterior 
  to 
  the 
  middle. 
  

   The 
  third 
  and 
  fourth 
  segments 
  have 
  a 
  sharp 
  spine 
  on 
  each 
  side, 
  above 
  the 
  bran- 
  

   chiae 
  and 
  near 
  the 
  hinder 
  margin, 
  and 
  the 
  three 
  posterior 
  segments 
  are 
  furnished 
  

   with 
  similar 
  spines. 
  

  

  Length 
  of 
  body, 
  1 
  11-16 
  inch. 
  Length 
  of 
  superior 
  antennce, 
  about 
  1 
  inch. 
  

  

  Female. 
  Body 
  less 
  elongated 
  than 
  in 
  the 
  male 
  ; 
  third 
  and 
  fourth 
  segments 
  

   swollen 
  at 
  the 
  sides, 
  and 
  both 
  these 
  segments 
  armed 
  with 
  a 
  long, 
  sharp 
  spine, 
  

   the 
  point 
  curving 
  towards 
  the 
  head 
  ; 
  fifth 
  and 
  sixth 
  segments 
  armed 
  with 
  a 
  

   straight 
  spine. 
  Second 
  pair 
  of 
  legs 
  about 
  as 
  long 
  as 
  the 
  second 
  segment 
  of 
  

  

  