﻿A. 
  E. 
  Verrill 
  — 
  Echinoderms 
  of 
  Northeastern 
  America. 
  129 
  

  

  many 
  of 
  them 
  do 
  not 
  have 
  free-swimming 
  larvse, 
  but 
  bring 
  

   forth 
  well 
  developed 
  creeping 
  young 
  ; 
  as, 
  for 
  example, 
  the 
  

   Pterasteridfe, 
  Solasteridse, 
  Echinasteridse, 
  Astrophytonidae, 
  etc. 
  

   In 
  other 
  cases 
  the 
  eggs 
  are 
  so 
  large 
  as 
  to 
  indicate 
  that 
  the 
  

   larvse 
  (though 
  unknown) 
  are 
  unlike 
  those 
  of 
  shallow 
  water 
  

   species 
  and 
  not 
  free-swimming. 
  

  

  9. 
  It 
  is, 
  therefore, 
  probable 
  that 
  many 
  of 
  the 
  strictly 
  abyssal 
  

   species 
  do 
  not 
  have 
  the 
  benefit 
  of 
  the 
  transporting 
  agency 
  of 
  

   ocean 
  currents, 
  which 
  so 
  rapidly 
  transport 
  the 
  free 
  larvae 
  of 
  

   most 
  shallow-water 
  species. 
  If 
  that 
  be 
  the 
  case, 
  they 
  can 
  only 
  

   extend 
  their 
  range 
  by 
  the 
  extremely 
  slow 
  process 
  of 
  creeping 
  

   by 
  means 
  of 
  their 
  ambulacra! 
  feet, 
  which, 
  on 
  the 
  soft 
  ooze 
  of 
  

   the 
  sea 
  bottom, 
  must 
  be 
  a 
  very 
  slow 
  process. 
  

  

  10. 
  We 
  must, 
  therefore, 
  conclude 
  that 
  the 
  widely 
  diffused 
  

   abyssal 
  genera, 
  many 
  of 
  which 
  now 
  occupy 
  all 
  the 
  great 
  ocean 
  

   basins, 
  and 
  in 
  many 
  cases 
  range 
  from 
  the 
  Arctic 
  to 
  the 
  Ant- 
  

   arctic 
  Oceans, 
  are 
  of 
  very 
  great 
  antiquity, 
  and 
  that 
  there 
  has 
  

   been 
  ample 
  time, 
  since 
  they 
  occupied 
  the 
  deep 
  sea, 
  for 
  the 
  minor 
  

   differences 
  characteristic 
  of 
  species 
  to 
  originate 
  in 
  different 
  

   geographical 
  regions, 
  as 
  a 
  result 
  of 
  casual 
  variations 
  that 
  have 
  

   been 
  conserved 
  by 
  isolation, 
  perhaps 
  aided 
  in 
  some 
  cases 
  by 
  

   "natural 
  selection." 
  

  

  11. 
  In 
  the 
  majority 
  of 
  cases, 
  however, 
  there 
  is 
  no 
  evident 
  

   utility 
  in 
  the 
  characters 
  that 
  separate 
  one 
  abyssal 
  species 
  from 
  

   another 
  of 
  the 
  same 
  genus, 
  for 
  the 
  differences 
  are 
  generally 
  

   slight 
  modifications 
  of 
  form 
  arfd 
  color 
  ; 
  arrangement, 
  shape 
  and 
  

   size 
  of 
  the 
  spines, 
  granulations, 
  pedicellarise, 
  etc. 
  Such 
  differ- 
  

   ences 
  can 
  hardly 
  be 
  of 
  protective 
  value 
  in 
  the 
  darkness 
  and 
  

   quietness 
  of 
  the 
  depths 
  in 
  which 
  they 
  live. 
  

  

  Systematic 
  List 
  of 
  the 
  Starfishes, 
  with 
  their 
  Bathy 
  metrical 
  and 
  Geographical 
  Distri- 
  

   bution, 
  expressed 
  in 
  a 
  condensed 
  form. 
  * 
  

  

  ASTERIOIDEA, 
  

   Family 
  Aechasterid^: 
  (Viguier, 
  1878) 
  emended, 
  Sladen. 
  

  

  Benthopecten 
  spixosus 
  Verrill. 
  

  

  Benthopecten 
  spinosus 
  Verrill, 
  this 
  Journal, 
  vol. 
  xxviii, 
  p. 
  218, 
  1884; 
  Explora- 
  

   tions 
  made 
  by 
  the 
  Albatross 
  in 
  1883, 
  in 
  Annual 
  Report, 
  U. 
  S. 
  Comm. 
  of 
  Fish 
  

   and 
  Fisheries, 
  pp. 
  519 
  [17], 
  543 
  [41], 
  1885; 
  Proc. 
  Nat. 
  Mus., 
  vol. 
  xvii, 
  

   p. 
  245, 
  1894. 
  

  

  Pararchaster 
  semisquamatus 
  var. 
  occidentalis 
  Sladen, 
  Voyage 
  of 
  the 
  Challenger, 
  

   vol. 
  xxx. 
  p. 
  10, 
  1889. 
  

  

  Pararchaster 
  armatus 
  Sladen, 
  op. 
  cit., 
  p. 
  19, 
  pi. 
  1, 
  figs. 
  5, 
  6; 
  pi. 
  4, 
  figs. 
  5, 
  6, 
  

   1889. 
  

  

  * 
  In 
  this 
  list, 
  as 
  a 
  matter 
  of 
  convenience, 
  I 
  have 
  followed 
  pretty 
  nearly 
  the 
  

   arrangement 
  and 
  nomenclature 
  adopted 
  by 
  Mr. 
  Sladen 
  in 
  his 
  classical 
  work 
  on 
  

   the 
  Starfishes 
  collected 
  by 
  the 
  Challenger. 
  (Report 
  on 
  Scientific 
  Results, 
  Zoology, 
  

   vol. 
  xxx, 
  with 
  a 
  vol. 
  of 
  plates). 
  

  

  In 
  doing 
  this 
  I 
  do 
  not 
  necessarily 
  approve 
  of 
  all 
  the 
  changes 
  of 
  names 
  made 
  by 
  

   him. 
  In 
  several 
  cases 
  I 
  decline 
  to 
  follow 
  him 
  and 
  others 
  in 
  the 
  resurrection 
  of 
  

   the 
  ante-Linnsean 
  names 
  given 
  by 
  Linck. 
  To 
  do 
  this 
  systematically 
  would 
  pro- 
  

   duce 
  endless 
  confusion. 
  

  

  Am. 
  Jour. 
  Scl— 
  Third 
  Series, 
  Vol. 
  XLIX, 
  No. 
  290.— 
  Feb., 
  1895. 
  

   9 
  

  

  