﻿Bibliographical 
  Notices. 
  505 
  

  

  forms 
  was 
  hardly 
  possible, 
  and 
  the 
  descriptions 
  of 
  the 
  majority 
  were 
  

   so 
  insufficient 
  and 
  unsatisfactory 
  that 
  working 
  collectors 
  may 
  well 
  

   be 
  pardoned 
  for 
  shrinking 
  from 
  naming 
  additional 
  specimens 
  ac- 
  

   quired 
  from 
  time 
  to 
  time. 
  Thanks 
  to 
  the 
  author 
  of 
  the 
  present 
  

   monograph 
  this 
  chaos 
  is 
  now 
  dispelled, 
  and 
  light 
  is 
  at 
  last 
  admitted 
  

   into 
  the 
  domain 
  of 
  these 
  interesting 
  organisms. 
  

  

  The 
  Iteport 
  is 
  divided 
  into 
  the 
  seven 
  undermentioned 
  sections 
  : 
  — 
  

   I. 
  General 
  Introduction, 
  in 
  which 
  a 
  historical 
  sketch 
  is 
  given 
  of 
  our 
  

   knowledge 
  of 
  the 
  Comatuke. 
  II. 
  The 
  Centro-Dorsal 
  and 
  Calyx, 
  

   which 
  gives 
  a 
  comparative 
  morphological 
  review 
  of 
  the 
  principal 
  

   characters 
  which 
  distinguish 
  the 
  Comatulidas 
  from 
  the 
  other 
  Crinoids, 
  

   and 
  discusses 
  the 
  opinions 
  of 
  previous 
  writers 
  thereon. 
  III. 
  Gives 
  

   a 
  summary 
  of 
  the 
  Geographical 
  and 
  Bathymetrical 
  Distribution 
  of 
  

   the 
  Comatuke. 
  IV. 
  Treats 
  of 
  the 
  Geological 
  History 
  of 
  the 
  Coma- 
  

   tulae. 
  V. 
  Deals 
  with 
  Classification, 
  in 
  which 
  the 
  author 
  discusses 
  

   the 
  validity 
  and 
  relative 
  value 
  of 
  the 
  characters 
  used 
  for 
  specific 
  

   determination, 
  and 
  proposes 
  a 
  system 
  of 
  literal 
  formula? 
  by 
  which 
  

   the 
  characters 
  of 
  the 
  species 
  may 
  be 
  indicated, 
  the 
  method 
  adopted 
  

   by 
  Bell 
  in 
  1882 
  being 
  discussed 
  and 
  improved. 
  VI. 
  Is 
  devoted 
  to 
  

   the 
  description 
  of 
  the 
  specimens, 
  and 
  occupies 
  three 
  fourths 
  of 
  the 
  

   Keport 
  ; 
  each 
  genus 
  is 
  exhaustively 
  discussed, 
  and 
  tabular 
  keys 
  are 
  

   given 
  of 
  the 
  species 
  included 
  in 
  each 
  genus 
  or 
  section 
  of 
  a 
  genus. 
  

   VII. 
  Bathymetrical 
  Distribution 
  and 
  Station 
  List, 
  to 
  which 
  is 
  added 
  

   a 
  list 
  of 
  the 
  known 
  living 
  species 
  of 
  Comatuke. 
  

  

  The 
  following 
  brief 
  epitome 
  will 
  indicate 
  the 
  main 
  results 
  arrived 
  

   at 
  in 
  the 
  Keport. 
  

  

  The 
  family 
  ComatuhVke 
  (d'Orbigny) 
  as 
  amended 
  by 
  the 
  author 
  now 
  

   comprises 
  seven 
  genera, 
  the 
  general 
  relations 
  of 
  which 
  are 
  expressed 
  

   in 
  the 
  following 
  table 
  : 
  — 
  

  

  I. 
  Centro-dorsal 
  has 
  no 
  articular 
  facet 
  on 
  its 
  lower 
  

  

  surface. 
  

  

  A. 
  Five 
  rays. 
  

  

  i. 
  Mouth 
  central 
  or 
  subcentral. 
  Oral 
  pinnules 
  

   have 
  no 
  comb. 
  

  

  a. 
  Radials 
  separated 
  by 
  mterradials 
  Thaumatocrinus. 
  

  

  b. 
  Radials 
  united 
  laterally. 
  

  

  (1). 
  Basals 
  persist 
  as 
  a 
  closed 
  ring. 
  No 
  pin- 
  

   nules 
  on 
  lower 
  brachials 
  Atelecrinus. 
  

  

  {2). 
  Basal 
  ring 
  incomplete 
  or 
  invisible 
  ex- 
  

   ternally. 
  

  

  a. 
  Five 
  arms 
  only 
  Eudiocrinus. 
  

  

  [1. 
  Ten 
  arms 
  Arvtedon. 
  

  

  ii. 
  Mouth 
  excentric 
  or 
  marginal. 
  Oral 
  pinnules 
  

  

  have 
  a 
  terminal 
  comb 
  Actinometra. 
  

  

  B. 
  Ten 
  rays 
  Promachocrinus. 
  

  

  II. 
  Centro-dorsal 
  has 
  an 
  articular 
  facet 
  below 
  Tkiolliericrinus. 
  

  

  The 
  two 
  genera 
  Thatumaiocrinus 
  and 
  Promachowinus 
  were 
  dis- 
  

   covered 
  by 
  the 
  ' 
  Challenger.' 
  

  

  