﻿i6o 
  

  

  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  discriminately 
  over 
  the 
  coral 
  at 
  its 
  various 
  levels 
  of 
  growth. 
  How 
  

   well 
  it 
  struggled 
  to 
  maintain 
  itself 
  is 
  indicated 
  by 
  the 
  presence 
  of 
  

   fully 
  30 
  individuals 
  on 
  a 
  surface 
  of 
  this 
  coral 
  2 
  inches 
  square. 
  The 
  

   single 
  specimen 
  of 
  this 
  species 
  observed 
  is 
  from 
  the 
  Middle 
  Devonic 
  

   Cedar 
  Valley 
  beds 
  at 
  Iowa 
  City, 
  Iowa. 
  

  

  Worms 
  and 
  Sponges 
  

  

  We 
  find 
  in 
  more 
  than 
  a 
  single 
  instance 
  among 
  the 
  fossil 
  hexac- 
  

   tinellid 
  sponges 
  of 
  the 
  family 
  Dictyospongidae 
  evidences 
  of 
  worm 
  

   tubes 
  attached 
  to 
  the 
  inner 
  wall 
  or 
  cloaca 
  of 
  the 
  sponge 
  and 
  living 
  

   in 
  a 
  condition 
  of 
  commensalism. 
  Such 
  worms 
  have 
  been 
  observed 
  

   in 
  the 
  species 
  Hydnoceras 
  tuberosum 
  var. 
  glos- 
  

   s 
  e 
  m 
  a 
  and 
  Prismodictya 
  telum 
  Hall 
  & 
  Clarke, 
  from 
  

   the 
  sponge 
  plantations 
  of 
  the 
  Upper 
  Devonic 
  in 
  western 
  New 
  York 
  

   [pi. 
  5, 
  fig. 
  1, 
  2]. 
  In 
  a 
  considerable 
  number 
  of 
  individuals 
  of 
  the 
  

   latter 
  species 
  from 
  the 
  same 
  locality 
  nearly 
  all 
  showed 
  the 
  presence 
  

  

  of 
  the 
  annelid 
  commensal 
  and 
  as 
  the 
  surface 
  of 
  the 
  impression 
  left 
  

   in 
  the 
  sands 
  by 
  the 
  worm 
  tube 
  is 
  in 
  all 
  cases 
  crossed 
  by 
  the 
  reticu- 
  

   lated 
  skeleton 
  of 
  the 
  sponge 
  it 
  is 
  inferred 
  that 
  the 
  position 
  of 
  the 
  

  

  