﻿[7] 
  DECAPODA 
  FROM 
  ALBATROSS 
  DREDGINGS. 
  611 
  

  

  surface. 
  Species 
  well 
  known 
  to 
  be 
  inhabitants 
  of 
  the 
  surface 
  are 
  some- 
  

   times 
  found 
  in 
  the 
  trawl 
  (and 
  of 
  course 
  excluded 
  from 
  the 
  list 
  of 
  species 
  

   dredged), 
  but 
  are 
  rarely 
  so 
  taken. 
  

  

  The 
  first 
  fifteen 
  species 
  in 
  the 
  list, 
  and 
  44 
  and 
  45 
  as 
  well, 
  are 
  unques- 
  

   tionably 
  inhabitants 
  of 
  the 
  bottom, 
  and 
  never 
  swim 
  any 
  great 
  distance 
  

   from 
  it. 
  Nos. 
  16, 
  17, 
  18, 
  and 
  4G, 
  though 
  species 
  which 
  may 
  swim 
  freely 
  

   for 
  considerable 
  distances 
  from 
  the 
  bottom, 
  undoubtedly 
  rest 
  upon 
  it 
  

   a 
  part 
  of 
  the 
  time, 
  the 
  structure 
  of 
  the 
  pefaeopods 
  being 
  fitted, 
  appar- 
  

   ently, 
  to 
  do 
  this. 
  

  

  The 
  species 
  of 
  Acanthephyra, 
  Ephyrina, 
  Notostomus, 
  Meningodora, 
  and 
  

   Hymenodora, 
  which 
  are 
  very 
  much 
  alike 
  in 
  the 
  structure 
  of 
  the 
  articular 
  

   appendages 
  and 
  branchiae 
  and 
  are 
  here 
  grouped 
  together 
  as 
  Miersiidas, 
  

   are 
  among 
  the 
  most 
  common 
  and 
  characteristic 
  forms 
  taken 
  in 
  trawling 
  

   at 
  great 
  depths, 
  but 
  it 
  is 
  perhaps 
  doubtful 
  whether 
  any 
  of 
  them 
  are, 
  

   strictly 
  speaking, 
  inhabitants 
  of 
  the 
  bottom. 
  The 
  occurrence 
  at 
  the 
  

   surface 
  of 
  a 
  living 
  and 
  active 
  specimen 
  of 
  Acanthephyra 
  Agassizii, 
  shows 
  

   that 
  this 
  species 
  at 
  least 
  is 
  capable 
  of 
  living 
  at 
  the 
  surface 
  in 
  water 
  of 
  

   a 
  temperature 
  of 
  more 
  than 
  30 
  degrees 
  higher 
  than 
  that 
  of 
  the 
  abyssal 
  

   depths. 
  Such 
  facts 
  make 
  it 
  very 
  difficult 
  to 
  draw 
  any 
  conclusions 
  from 
  

   the 
  mere 
  finding 
  of 
  specimens 
  of 
  any 
  free-swimining 
  species 
  in 
  the 
  trawl 
  

   coining 
  from 
  particular 
  depths, 
  and 
  we 
  are 
  compelled 
  to 
  resort 
  to 
  the 
  

   structure 
  of 
  the 
  animal 
  itself 
  for 
  evidence 
  as 
  to 
  the 
  depth 
  of 
  its 
  habitat. 
  

   The 
  highly 
  developed 
  black 
  eyes, 
  the 
  comparatively 
  small 
  eggs, 
  and 
  the 
  

   firm 
  integument 
  of 
  A. 
  Agassizii 
  and 
  A. 
  cximea 
  are 
  some 
  evidence, 
  though 
  

   perhaps 
  inconclusive, 
  that 
  these 
  species 
  do 
  not 
  normally 
  iuhabit 
  the 
  

   greatest 
  depths 
  from 
  which 
  the 
  former 
  species 
  has 
  been 
  recorded 
  ; 
  and 
  

   neither 
  the 
  length 
  nor 
  the 
  structure 
  of 
  the 
  perseopods 
  shows 
  special 
  adap- 
  

   tation 
  for 
  resting 
  on 
  soft 
  oozy 
  bottoms. 
  We 
  are 
  therefore 
  led 
  to 
  con- 
  

   clude 
  that 
  these 
  two 
  species 
  normally 
  inhabit 
  the 
  upper 
  part 
  of 
  the 
  vast 
  

   space 
  between 
  the 
  surface 
  and 
  the 
  bottom 
  regions. 
  The 
  similarity 
  in 
  the 
  

   structure 
  of 
  the 
  perseopodsin 
  all 
  the 
  species 
  of 
  the 
  genus 
  except 
  A. 
  gra- 
  

   cilis, 
  apparently 
  indicates 
  similarity 
  in 
  habits, 
  but 
  the 
  imperfectly 
  de- 
  

   veloped 
  eyes 
  and 
  soft 
  integument 
  of 
  A. 
  microphthalma 
  and 
  brevirostris 
  

   are 
  evidence 
  that 
  these 
  species 
  inhabit 
  greater 
  depths 
  than 
  A. 
  Agas- 
  

   sizii 
  and 
  cximea, 
  and 
  that 
  they 
  are 
  truly 
  abyssal 
  if 
  not 
  bottom-inhabit- 
  

   ing 
  species, 
  and 
  their 
  absence 
  from 
  the 
  trawl 
  when 
  coming 
  from 
  moder- 
  

   ate 
  depths, 
  as 
  shown 
  in 
  the 
  records 
  of 
  their 
  capture, 
  helps 
  to 
  confirm 
  this. 
  

   The 
  small 
  number 
  and 
  great 
  size 
  of 
  the 
  eggs 
  of 
  A. 
  gracilis 
  would 
  seem 
  

   to 
  indicate 
  an 
  abyssal 
  habitat 
  for 
  that 
  species 
  aiso, 
  but 
  the 
  large 
  black 
  

   eyes 
  are 
  probable 
  evidence 
  that 
  it 
  does 
  not 
  descend 
  to 
  the 
  extreme 
  

   depths 
  inhabited 
  by 
  A. 
  microphthalma. 
  

  

  Their 
  similarity 
  of 
  structure 
  makes 
  it 
  probable 
  that 
  the 
  species 
  of 
  

   Ephyrina, 
  Notostomus, 
  Meningodora, 
  and 
  Hymenodora 
  are 
  similar 
  in 
  hab- 
  

   its 
  to 
  the 
  species 
  of 
  Acanthephyra, 
  and 
  the 
  structure 
  of 
  their 
  eyes 
  and 
  

   integument 
  and 
  the 
  small 
  number 
  and 
  great 
  size 
  of 
  the 
  eggs, 
  in 
  the 
  spe- 
  

  

  