﻿112 
  Twenty-eighth 
  Eepoet 
  on 
  the 
  State 
  Museum. 
  

  

  gins 
  in 
  well-preserved 
  SDecimens 
  distinctly 
  elevated, 
  and 
  fre- 
  

   quently 
  finely 
  serrated. 
  

  

  In 
  ^specimens 
  where 
  the 
  maculate 
  surface 
  is 
  well-preserved, 
  

   the 
  adjacent 
  cell-apertures 
  often 
  have 
  their 
  longest 
  diameter 
  

   in 
  a 
  radiating 
  direction 
  from 
  the 
  center 
  of 
  the 
  maculae. 
  The 
  

   cell-apertures 
  in 
  this 
  species 
  vary 
  from 
  circular 
  to 
  elongate- 
  

   oval 
  or 
  ovate, 
  both 
  forms 
  sometimes 
  occurring 
  on 
  the 
  same 
  

   specimen, 
  while 
  in 
  worn 
  specimens 
  the 
  apertures 
  appear 
  to 
  

   be 
  polygonal. 
  

  

  Trematopora 
  echinata. 
  

  

  Plate 
  11, 
  Figs. 
  1-5. 
  

  

  Trematopora 
  echinata 
  Hall. 
  Doc. 
  Edit. 
  28th 
  Rep. 
  St. 
  Mus. 
  Nat. 
  Hist. 
  Expla- 
  

   nation 
  of 
  pi. 
  11, 
  figs. 
  1-5. 
  1876. 
  

  

  Bryozoum 
  solid, 
  ramose 
  ; 
  branches 
  from 
  .75 
  to 
  1.5 
  mm. 
  in 
  

   diameter, 
  frequently 
  widely 
  diverging, 
  sometimes 
  at 
  an 
  angle 
  of 
  

   80° 
  or 
  90°. 
  Cell-tubes 
  polygonal, 
  generally 
  hexagonal, 
  com- 
  

   mencing 
  at 
  the 
  center 
  of 
  the 
  branch 
  and 
  gradually 
  diverging 
  

   to 
  near 
  the 
  surface, 
  where 
  they 
  turn 
  abruptly 
  outward. 
  Cell- 
  

   apertures 
  longer 
  than 
  wide, 
  length 
  from 
  about 
  .3 
  mm. 
  to 
  .55 
  

   mm., 
  the 
  width 
  being 
  from 
  one-half 
  to 
  two-thirds 
  their 
  length, 
  

   having 
  at 
  the 
  angles 
  of 
  the 
  margins 
  slender, 
  sharp 
  spines. 
  

  

  This 
  species 
  is 
  very 
  abundant, 
  often 
  nearly 
  covering 
  the 
  sur- 
  

   faces 
  of 
  the 
  calcareous 
  slabs, 
  and 
  imbedded 
  in 
  the 
  softer 
  

   shales. 
  It 
  presents 
  much 
  variation 
  in 
  the 
  size 
  of 
  the 
  cell-aper- 
  

   tures, 
  and 
  their 
  distribution 
  on 
  the 
  surface 
  is 
  sometimes 
  inter- 
  

   rupted 
  and 
  irregular. 
  The 
  prevailing 
  form 
  is 
  represented 
  in 
  

   fig. 
  4, 
  plate 
  11. 
  In 
  many 
  examples 
  the 
  smaller 
  stipes 
  and 
  

   branches 
  are 
  marked 
  by 
  the 
  larger 
  cell-apertures. 
  

  

  Trematopora 
  granulifera. 
  

  

  Plate 
  11, 
  Figs. 
  6, 
  7. 
  

  

  Trematopora 
  granulif 
  era. 
  Hall,. 
  Pal. 
  N. 
  Y. 
  vol. 
  ii, 
  page 
  154, 
  pi. 
  40 
  A. 
  figs. 
  9a, 
  

  

  9c. 
  1852. 
  

   Trematopora 
  granulifera 
  (n. 
  sp. 
  in 
  error.) 
  Hall.. 
  Doc. 
  Ed., 
  28th 
  Rep. 
  St. 
  Mus. 
  

  

  Nat. 
  Hist, 
  explanation 
  of 
  pi. 
  II, 
  figs. 
  6, 
  7. 
  1876. 
  

   Compare 
  T. 
  regularis 
  Hall. 
  26th 
  Rep. 
  N. 
  Y. 
  St. 
  Mus. 
  Nat. 
  Hist., 
  p. 
  106. 
  1873. 
  

  

  Bryozoum 
  ramose, 
  solid 
  ; 
  branches 
  one 
  millimetre 
  or 
  less 
  in 
  

   diameter. 
  Cells 
  tubular 
  oval, 
  rising 
  from 
  the 
  center 
  of 
  the 
  

   branch 
  and 
  increasing 
  by 
  interstitial 
  additions. 
  Length 
  of 
  

  

  