﻿154 
  MR. 
  F. 
  A. 
  BATHER 
  ON 
  TRIG02TOCRTNUS 
  FROM 
  

  

  marine 
  bodies. 
  The 
  calyx 
  is 
  formed 
  of 
  radials 
  alone, 
  without 
  basals. 
  

   The 
  first 
  radials, 
  which 
  may 
  vary 
  in 
  number, 
  are 
  closely 
  united 
  to 
  one 
  

   another, 
  and 
  enclose 
  the 
  true 
  calycal 
  cavity. 
  Their 
  united 
  base 
  is 
  

   truncate 
  or 
  depressed 
  for 
  the 
  articular 
  facet 
  of 
  the 
  stem 
  ; 
  they 
  may 
  also, 
  

   but 
  more 
  rarely, 
  rest 
  on 
  a 
  well-characterized 
  ' 
  article 
  basal.' 
  Their 
  

   upper 
  face 
  bears 
  a 
  well-developed 
  articular 
  surface, 
  on 
  which 
  is 
  

   articulated 
  a 
  second 
  radial, 
  surmounted 
  by 
  a 
  third 
  axillary 
  radial, 
  

   The 
  arms 
  are 
  scarcely 
  known. 
  One 
  species 
  only 
  * 
  shows 
  them 
  to 
  

   the 
  number 
  of 
  ten, 
  not 
  branched, 
  rolled 
  up, 
  and 
  composed 
  of 
  a 
  

   single 
  series 
  of 
  thick 
  joints. 
  The 
  stem-joints 
  are 
  usually 
  long, 
  and 
  

   were 
  probably 
  few 
  in 
  number 
  ; 
  their 
  articular 
  facets 
  bear 
  ridges 
  or 
  

   irregular 
  crenellations. 
  There 
  are 
  no 
  cirri. 
  The 
  root 
  is 
  a 
  little 
  cal- 
  

   careous 
  mass 
  or 
  a 
  flattened 
  incrustation." 
  De 
  Loriol 
  includes 
  in 
  

   this 
  family 
  the 
  genera 
  Eugeniacrinus, 
  Phyllocrinus, 
  Eudesicrinus, 
  

   and 
  Tetracrinus. 
  On 
  the 
  grounds 
  of 
  general 
  resemblance 
  in 
  the 
  

   disposition 
  of 
  the 
  radials, 
  of 
  the 
  entire 
  absence 
  of 
  the 
  radial 
  pro- 
  

   cesses 
  so 
  characteristic 
  of 
  most, 
  though 
  not 
  all 
  Eugeniacrinidse, 
  and 
  

   of 
  the 
  single-jointed 
  stem, 
  Euchsicrinus 
  must 
  be 
  referred 
  to 
  the 
  

   Holopidse. 
  Dr. 
  P. 
  H. 
  Carpenter, 
  who 
  has 
  already 
  made 
  this 
  cor- 
  

   rectionf, 
  believes 
  that 
  the 
  peculiar 
  support 
  consists 
  of 
  basals 
  fused 
  

   to 
  one 
  another 
  and 
  to 
  a 
  single 
  stem-joint 
  below. 
  In 
  this 
  I 
  follow 
  

   Carpenter 
  in 
  preference 
  to 
  de 
  Loriol. 
  Carpenter, 
  however, 
  also 
  

   believes 
  that 
  the 
  "article 
  basal," 
  usually 
  known 
  as 
  % 
  the 
  top 
  stem- 
  

   joint, 
  of 
  Eugeniacrinidse 
  represents 
  fused 
  basals*. 
  If 
  this 
  were 
  

   true, 
  the 
  distinction 
  between 
  the 
  two 
  families 
  Holopidse 
  and 
  Eu- 
  

   geniacrinidse 
  would 
  seem 
  confined 
  to 
  the 
  difference 
  in 
  number 
  of 
  

   stem-joints 
  ; 
  while, 
  on 
  the 
  other 
  hand, 
  the 
  Eugeniacrinidse 
  would 
  be 
  

   very 
  closely 
  allied 
  to 
  Ehizocrinus 
  and 
  the 
  Bourgueticrinidae. 
  On 
  

   this 
  point, 
  however, 
  I 
  am 
  at 
  present 
  unable 
  to 
  agree 
  with 
  Dr. 
  Car- 
  

   penter. 
  It 
  will 
  be 
  necessary 
  to 
  recur 
  to 
  this 
  question 
  ; 
  meanwhile 
  

   I 
  adopt 
  the 
  explanation 
  of 
  Eeyrich 
  and 
  Zittel, 
  that 
  the 
  basals 
  have 
  

   T)een 
  included 
  and 
  absorbed 
  by 
  the 
  radials. 
  

  

  Erom 
  the 
  Eugeniacrinidae, 
  as 
  thus 
  conceived 
  and 
  limited, 
  the 
  

   form 
  with 
  which 
  we 
  have 
  now 
  to 
  deal, 
  differs 
  in 
  the 
  following 
  cha- 
  

   racters: 
  — 
  Eirst, 
  in 
  the 
  presence 
  of 
  what 
  I 
  have 
  called 
  a 
  "basal 
  

   ring," 
  which 
  I 
  believe 
  to 
  represent 
  fused 
  basals 
  ; 
  secondly, 
  in 
  the 
  

   absence 
  or 
  extremely 
  slight 
  development 
  of 
  an 
  articular 
  surface 
  for 
  

   a 
  second 
  radial 
  ; 
  and 
  I 
  think 
  we 
  may 
  add 
  as 
  thirdly, 
  that 
  it 
  differs 
  

   in 
  the 
  number 
  and 
  arrangement 
  of 
  its 
  radials. 
  It 
  is 
  true 
  that 
  

   Eugeniacrinus 
  and, 
  possibly, 
  Phyllocrinus 
  have 
  occasionally 
  only 
  

   four 
  radials, 
  and 
  that 
  Tetracrinus 
  has 
  that 
  number 
  as 
  a 
  rule. 
  The 
  

   common 
  opinion 
  is 
  that 
  such 
  a 
  variation 
  is 
  rather 
  common 
  in 
  

   Eugeniacrinus 
  ; 
  absolutely, 
  this 
  may 
  be 
  true 
  ; 
  but, 
  having 
  regard 
  to 
  

   the 
  enormous 
  number 
  of 
  specimens, 
  I 
  believe 
  that 
  the 
  relative 
  

  

  * 
  Etigeniacr. 
  nutans, 
  Goldf. 
  {vide 
  Zittel, 
  he. 
  cit. 
  fig. 
  273 
  h).— 
  R 
  A. 
  B. 
  

   t 
  Report 
  ' 
  Challenger 
  ' 
  Zoology, 
  vol. 
  xi. 
  part 
  xxxii. 
  Crinoidea 
  : 
  I. 
  Stalked 
  

   Crinoids, 
  p. 
  216 
  (London, 
  1884). 
  

  

  J 
  " 
  On 
  the 
  supposed 
  absence 
  of 
  Basals 
  in 
  the 
  Eugeniacrinidas 
  and 
  in 
  certain 
  

   ■other 
  Neocrinoids.'' 
  Ann. 
  & 
  Mag. 
  Nat. 
  Hist. 
  5th 
  ser. 
  xi. 
  pp. 
  327-334 
  (May 
  

   1883). 
  

  

  