﻿1 
  66 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  tegmen, 
  or 
  a 
  specimen 
  of 
  Onychaster 
  between 
  the 
  arms 
  and 
  coiled 
  

   around 
  the 
  anal 
  tube. 
  This, 
  so 
  far 
  as 
  we 
  know, 
  is 
  the 
  first 
  instance 
  

   in 
  which 
  a 
  Platyceras 
  has 
  been 
  found 
  in 
  contact 
  with 
  a 
  Crinoid 
  

   with 
  a 
  long 
  anal 
  tube; 
  in 
  all 
  cases 
  heretofore 
  noticed 
  the 
  Crinoid 
  

   had 
  an 
  anal 
  opening 
  directly 
  through 
  the 
  tegmen, 
  and 
  the 
  Gas- 
  

   tropod 
  was 
  fastened 
  invariably 
  with 
  the 
  anterior 
  portion 
  of 
  the 
  

   shell 
  over 
  the 
  opening. 
  This 
  led 
  to 
  the 
  supposition, 
  for 
  which 
  

   there 
  seemed 
  to 
  be 
  good 
  reasons, 
  that 
  the 
  Mollusk 
  obtained 
  its 
  

   nourishment, 
  in 
  part 
  at 
  least, 
  from 
  the 
  excrements 
  of 
  the 
  Crinoid. 
  

   This, 
  however, 
  was 
  impossible 
  in 
  the 
  case 
  before 
  us, 
  where 
  the 
  

   anal 
  tube, 
  with 
  the 
  anus 
  at 
  the 
  distal 
  end, 
  extends 
  out 
  far 
  beyond 
  

   the 
  tips 
  of 
  the 
  arms, 
  and, 
  so 
  far 
  as 
  observed, 
  bends 
  abruptly 
  to 
  

   one 
  side, 
  so 
  that 
  neither 
  the 
  opening 
  nor 
  the 
  refuse 
  matter 
  could 
  

   have 
  been 
  in 
  contact 
  with 
  the 
  Mollusk, 
  

  

  In 
  more 
  frequent 
  association 
  with 
  this 
  Actmocrinus 
  is 
  the 
  

   Onychaster, 
  and 
  it 
  is 
  worthy 
  of 
  note 
  that 
  this 
  species 
  of 
  ophiuran 
  

   is 
  rarely 
  found 
  by 
  itself. 
  Nor 
  has 
  it 
  been 
  observed 
  at 
  Indian 
  

   Creek 
  on 
  any 
  of 
  the 
  other 
  Crinoids, 
  while 
  at 
  Canton 
  it 
  appears 
  also 
  

   on 
  most 
  of 
  the 
  specimens 
  of 
  Scytalocrinus 
  robustus 
  (Hall), 
  

   a 
  species 
  with 
  a 
  large 
  ventral 
  tube, 
  and 
  the 
  anus 
  located 
  far 
  down 
  

   at 
  the 
  anterior 
  side; 
  but 
  with 
  this 
  exception 
  we 
  have 
  not 
  seen 
  it 
  

   on 
  any 
  other 
  species. 
  The 
  fact 
  that 
  this 
  Ophiurid 
  is 
  only 
  found 
  

   associated 
  with, 
  certain 
  species, 
  and 
  there 
  always 
  under 
  similar 
  

   conditions, 
  and 
  the 
  frequency 
  of 
  this 
  occurrence, 
  would 
  seem 
  to 
  

   indicate 
  that 
  the 
  position 
  between 
  the 
  arms 
  of 
  these 
  crinoids 
  was 
  

   its 
  favorite 
  resting 
  place, 
  in 
  which 
  it 
  either 
  found 
  protection, 
  or 
  

   some 
  special 
  facility 
  for 
  obtaining 
  nourishment. 
  

  

  These 
  specimens 
  are 
  from 
  the 
  Crawfordsville 
  limeshale 
  of 
  the 
  

   Lower 
  Carbonic 
  (Mississippian). 
  

  

  Crinoids 
  and 
  Myzostomum 
  

   All 
  the 
  known 
  living 
  species 
  of 
  the 
  minute 
  wormlike 
  creature 
  

   Myzostomum 
  (60 
  to 
  70 
  in 
  number) 
  are 
  parasitic 
  on 
  the 
  crinoids 
  

   whereon 
  they 
  form 
  galls 
  or 
  swellings 
  by 
  the 
  overgrowth 
  of 
  the 
  

   test. 
  Similar 
  galls 
  have 
  been 
  noted 
  on 
  both 
  Mesozoic 
  and 
  Paleo- 
  

   zoic 
  species 
  of 
  crinoids 
  by 
  Bather, 
  Shipley, 
  Fraas 
  and 
  other 
  

   writers, 
  and 
  they 
  are 
  generally 
  ascribed 
  to 
  the 
  Myzostoma. 
  

  

  Coral 
  on 
  a 
  Coral 
  

   The 
  case 
  of 
  Caunopora. 
  It 
  is 
  now 
  quite 
  generally 
  conceded 
  that 
  

   Caunopora 
  which 
  has 
  commonly 
  been 
  regarded 
  as 
  a 
  hydroid 
  coral 
  

   like 
  Stromatopora, 
  but 
  with 
  sharply 
  defined, 
  definitely 
  walled 
  tubes, 
  

   is 
  actually 
  a 
  laminate 
  hydroid 
  overgrowing 
  a 
  series 
  of 
  erect 
  tubes 
  

   like 
  those 
  of 
  Syringopora 
  or 
  Aulopora, 
  carrying 
  oblique 
  dis- 
  

   sepiments 
  within. 
  Caunopora 
  placenta 
  Phillips 
  is 
  a 
  

   Devonic 
  species. 
  

  

  