﻿506 
  Bibliographical 
  Notices. 
  

  

  Thaumatocrinus, 
  Carpenter, 
  is 
  a 
  remarkably 
  archaic 
  form, 
  cha- 
  

   racterized 
  by 
  persistent 
  basal 
  and 
  oral 
  plates 
  — 
  the 
  latter 
  occurring 
  

   in 
  no 
  other 
  Comatulid 
  ; 
  primary 
  interradial 
  plates 
  which 
  separate 
  

   the 
  radials 
  are 
  also 
  present. 
  It 
  is 
  represented 
  by 
  one 
  species, 
  which 
  

   has 
  been 
  found 
  only 
  in 
  the 
  Southern 
  Ocean 
  at 
  a 
  depth 
  of 
  1800 
  

   fathoms. 
  

  

  Atelecrinus, 
  Carpenter, 
  is 
  characterized 
  by 
  the 
  persistence 
  of 
  the 
  

   embryonic 
  basals, 
  which 
  do 
  not 
  undergo 
  transformation 
  into 
  a 
  

   rosette, 
  and 
  by 
  the 
  absence 
  of 
  pinnules 
  from 
  the 
  lowest 
  joints 
  of 
  the 
  

   arms, 
  characters 
  which 
  mark 
  the 
  genus 
  as 
  a 
  permanent 
  larval 
  form. 
  

   Three 
  species 
  are 
  known, 
  two 
  from 
  the 
  Atlantic 
  and 
  one 
  from 
  the 
  

   Pacific. 
  Ono 
  of 
  the 
  Atlantic 
  species 
  occurs 
  off 
  Havana 
  in 
  450 
  

   fathoms, 
  and 
  the 
  other 
  in 
  the 
  Caribbean 
  Sea 
  and 
  off 
  rernambuco 
  in 
  

   depths 
  ranging 
  from 
  291 
  to 
  422 
  fathoms. 
  The 
  Pacific 
  species 
  was 
  

   dredged 
  near 
  Fiji 
  in 
  610 
  fathoms. 
  

  

  Eudiocrinus, 
  Carpenter, 
  has 
  a 
  centro-dorsal 
  and 
  calyx 
  like 
  those 
  

   of 
  Antedon 
  ; 
  but 
  the 
  radials 
  bear 
  the 
  brachials 
  directly 
  without 
  the 
  

   intervention 
  of 
  axillaries, 
  so 
  that 
  there 
  are 
  only 
  five 
  undivided 
  arms. 
  

   Five 
  species 
  are 
  known, 
  four 
  from 
  the 
  Western 
  Pacific 
  (off 
  Japan, 
  

   the 
  Philippine 
  Islands, 
  South-east 
  Australia, 
  and 
  .New 
  Zealand, 
  in 
  

   depths 
  varying 
  from 
  shallow 
  water 
  to 
  1050 
  fathoms) 
  and 
  one 
  from 
  

   the 
  Atlantic, 
  at 
  about 
  45° 
  N., 
  from 
  486 
  fathoms. 
  

  

  Antedon, 
  de 
  Freminville, 
  contains 
  the 
  large 
  number 
  of 
  120 
  recent 
  

   species. 
  These 
  have 
  been 
  separated 
  by 
  the 
  author 
  into 
  groups 
  or 
  

   alliances 
  of 
  species, 
  determined 
  by 
  the 
  character 
  of 
  the 
  rays 
  and 
  of 
  

   their 
  subdivisions. 
  The 
  groups 
  are 
  not 
  only 
  well 
  defined 
  as 
  regards 
  

   their 
  morphological 
  characters, 
  but 
  are 
  also 
  more 
  or 
  less 
  definitely 
  

   limited 
  in 
  their 
  distribution 
  both 
  bathymctrical 
  and 
  geogra- 
  

   phical. 
  Four 
  scries 
  and 
  ten 
  groups 
  are 
  defined, 
  the 
  latter 
  being 
  

   named 
  after 
  the 
  first 
  described 
  or 
  most 
  characteristic 
  species. 
  These 
  

   divisions 
  of 
  the 
  genus 
  may 
  be 
  thus 
  tabulated 
  : 
  — 
  

  

  I. 
  The 
  two 
  outer 
  radials 
  united 
  by 
  syzygy 
  elcgans 
  -group. 
  

  

  II. 
  The 
  two 
  outer 
  radials 
  articulated 
  ; 
  ten 
  arms. 
  

  

  a. 
  The 
  radials 
  and 
  brachials 
  have 
  flattened 
  sides. 
  

  

  Pinnule-ambulacra 
  generally 
  plated 
  basiewva-growp. 
  

  

  b. 
  The 
  rays 
  not 
  flattened 
  laterally. 
  Pinnule-ani- 
  

  

  bulacra 
  well 
  plated 
  acos/a-group. 
  

  

  c. 
  The 
  first 
  two 
  or 
  three 
  pairs 
  of 
  pinnules 
  long 
  and 
  

  

  flagellate, 
  with 
  numerous 
  short 
  and 
  wide 
  

  

  joints 
  Enchriehti-grou-p. 
  

  

  d. 
  The 
  joints 
  of 
  the 
  lowest 
  pinnules, 
  which 
  are 
  often 
  

  

  long 
  and 
  slender, 
  are 
  longer 
  than 
  wide, 
  fre- 
  

   quently 
  very 
  much 
  so 
  tenella-growp. 
  

  

  e. 
  The 
  first 
  pair 
  of 
  pinnules 
  are 
  comparatively 
  small 
  

  

  and 
  their 
  joints 
  but 
  little 
  longer 
  than 
  wide 
  ; 
  

   one 
  or 
  more 
  of 
  the 
  second, 
  third, 
  and 
  fourth 
  

   pairs 
  are 
  longer 
  and 
  more 
  massive, 
  with 
  

   stouter 
  joints 
  than 
  their 
  successors 
  3filbcrti-group. 
  

  

  