﻿FOURTH 
  REPORT 
  OF 
  THE 
  DIRECTOR 
  KJOJ 
  1 
  55 
  

  

  growing 
  obliquely 
  upward 
  from 
  the 
  very 
  beginning 
  of 
  the 
  coral 
  

   (Monticulipora) 
  growth. 
  This 
  soecimen 
  is 
  from 
  the 
  Onondaga 
  

   limestone. 
  

  

  A 
  very 
  similar 
  combination 
  is 
  shown 
  in 
  figure 
  3, 
  plate 
  i, 
  which 
  

   represents 
  a 
  colony 
  of 
  Favosites 
  sphericus 
  (Helder- 
  

   bergian) 
  with 
  worms 
  of 
  like 
  character. 
  Figures 
  1, 
  2 
  are 
  of 
  a 
  

   Stromatopora 
  from 
  the 
  Cobleskill 
  (Uppermost 
  Siluric) 
  limestone, 
  

   one 
  showing 
  the 
  worm 
  apertures 
  on 
  the 
  weathered 
  surface, 
  the 
  

   other 
  being 
  a 
  polished 
  face 
  of 
  the 
  same 
  specimen 
  with 
  many 
  

   cross-sections 
  of 
  oblique 
  tubes. 
  

  

  The 
  tabulate 
  coral 
  Pleurodictyum 
  ; 
  the 
  worm 
  Hicetes 
  innexus; 
  

   a 
  sponge, 
  and 
  the 
  gastropod 
  Loxonema 
  (sometimes 
  Pleurotomaria) 
  

   or 
  the 
  brachiopod 
  Chonetes 
  [see 
  plates 
  3, 
  4]. 
  This 
  is 
  a 
  very 
  remark- 
  

   able 
  and 
  most 
  instructive 
  combination 
  and 
  w 
  T 
  e 
  have 
  illustrated 
  it 
  

   quite 
  fully 
  on 
  the 
  accompanying 
  plates. 
  The 
  combination 
  of 
  the 
  

   coral 
  and 
  the 
  worm 
  has 
  long 
  been 
  known 
  and 
  the 
  sandstone 
  casts 
  

   of 
  the 
  base 
  of 
  Pleurodictyum 
  with 
  the 
  "coiled 
  central 
  body" 
  or 
  

   "wormlike 
  object" 
  are 
  common 
  in 
  the 
  Lower 
  Devonic 
  (Coblentzian) 
  

   of 
  Germany 
  and 
  have 
  frequently 
  been 
  illustrated. 
  

  

  Pleurodictyum 
  is 
  a 
  compound 
  coral 
  growing 
  in 
  small 
  lens 
  shaped 
  

   colonies 
  with 
  large 
  cells 
  and 
  the 
  genus 
  is 
  widely 
  distributed 
  in 
  

   fau 
  ^as 
  of 
  Lower 
  and 
  Middle 
  Devonic 
  time. 
  We 
  may 
  mention 
  P. 
  

   lenticulare 
  Hall 
  of 
  the 
  Helderbergian 
  of 
  New 
  York 
  and 
  its 
  

   variety' 
  laurentinum 
  of 
  the 
  Grande 
  Greve 
  limestone 
  of 
  

   Gaspe; 
  P. 
  convexum 
  Hall, 
  Onondaga 
  limestone 
  ;P. 
  proble- 
  

   m 
  a 
  t 
  i 
  c 
  u 
  m 
  Goldfuss 
  of 
  the 
  Coblentzian 
  ; 
  P. 
  Constantino- 
  

   p 
  o 
  1 
  i 
  t 
  a 
  n 
  u 
  m 
  Archiac 
  and 
  Verneuil, 
  from 
  the 
  lowest 
  Devonic 
  of 
  

   the 
  Bosphorus; 
  P. 
  amazonicum 
  Katzer 
  of 
  a 
  similar 
  age 
  in 
  the 
  

   Amazonas 
  and 
  P. 
  stylo 
  porum 
  Eaton 
  from 
  the 
  Middle 
  Devonic 
  

   Hamilton 
  shales 
  of 
  New 
  York. 
  The 
  concurrence 
  of 
  the 
  coral 
  and 
  

   its 
  convoluted 
  worm 
  has 
  been 
  noted 
  in 
  several 
  of 
  the 
  species 
  here 
  

   mentioned 
  but 
  the 
  varying 
  degree 
  of 
  its 
  frequency 
  is 
  instructive. 
  

   Thus 
  in 
  the 
  earliest 
  species, 
  P. 
  lenticulare, 
  I 
  have 
  seen 
  the 
  

   worm 
  tube 
  very 
  rarely, 
  after 
  the 
  examination 
  of 
  a 
  considerable 
  

   number 
  of 
  examples; 
  in 
  the 
  var. 
  laurentinum 
  not 
  at 
  all; 
  

   never 
  in 
  the 
  large 
  species 
  P. 
  convexum 
  Hall 
  of 
  the 
  Onondaga 
  

   limestone. 
  The 
  single 
  illustrations 
  of 
  P. 
  amazonicum 
  and 
  

   P. 
  constantinopolitanum 
  show 
  its 
  presence 
  but 
  enable 
  

   one 
  to 
  form 
  no 
  conception 
  of 
  its 
  prevalence. 
  The 
  combination 
  is 
  

   frequent 
  enough 
  in 
  P. 
  problematicumto 
  have 
  given 
  rise 
  to 
  

   the 
  specific 
  name 
  of 
  the 
  coral. 
  The 
  Middle 
  Devonic 
  P. 
  stylo- 
  

  

  