﻿204 
  

  

  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  branchlets 
  are 
  liable 
  to 
  form 
  so 
  dense 
  a 
  mass 
  that 
  they 
  completely 
  

   envelop 
  the 
  main 
  branch. 
  No 
  fructification 
  has 
  been 
  observed. 
  

  

  This 
  alga 
  probably 
  possessed 
  a 
  very 
  delicate 
  and 
  minute 
  thallus, 
  

   the 
  largest 
  fragments 
  not 
  attaining 
  20 
  mm 
  in 
  length. 
  The 
  car- 
  

   bonaceous 
  test 
  of 
  the 
  branches 
  is 
  much 
  thinner 
  than 
  in 
  the 
  genotype 
  

   and 
  also 
  than 
  that 
  of 
  the 
  associated 
  algae 
  in 
  the 
  Trenton 
  limestone 
  

   at 
  Glens 
  Falls 
  and 
  only 
  visible 
  with 
  good 
  light. 
  

  

  From 
  the 
  genotype 
  it 
  is 
  distinguished 
  by 
  the 
  generally 
  greater 
  

   tenderness 
  of 
  the 
  whole 
  thallus, 
  that 
  finds 
  its 
  expression 
  in 
  the 
  

   thinner 
  main 
  branch 
  and 
  thinner 
  and 
  more 
  flaccid 
  branchlets 
  and 
  

   also 
  in 
  the 
  closer 
  arrangement 
  of 
  the 
  whorls 
  on 
  the 
  main 
  stipe. 
  

   The 
  contraction 
  of 
  the 
  latter 
  between 
  the 
  annuli 
  produced 
  by 
  the 
  

   bases 
  of 
  the 
  whorled 
  branchlets 
  constitutes 
  another 
  difference. 
  

  

  Horizon 
  and 
  locality. 
  In 
  the 
  Trenton 
  limestone 
  at 
  Glens 
  Falls, 
  

   N. 
  Y. 
  

  

  Chaetocladus 
  Whitfield 
  

  

  For 
  a 
  new 
  species 
  of 
  supposed 
  algae 
  from 
  Platteville, 
  Wis., 
  Pro- 
  

   fessor 
  Whitfield 
  has 
  proposed 
  the 
  genus 
  Chaetocladus, 
  character- 
  

   izing 
  the 
  same 
  as 
  consisting 
  of 
  " 
  Marine 
  plants 
  with 
  jointed 
  cylin- 
  

   drical 
  stems 
  giving 
  off 
  whorls 
  of 
  hairlike 
  filaments 
  at 
  given 
  dis- 
  

   tances." 
  

  

  Chaetocladus 
  plum 
  ti 
  la 
  Whitfield 
  

  

  f 
  Fig. 
  II 
  Type 
  specimen, 
  xs 
  

  

  Fig. 
  12, 
  13 
  Further 
  enlargements. 
  (Copies 
  from 
  Whitfield) 
  

  

  We 
  insert 
  the 
  original 
  drawings 
  [^^^'text 
  fig. 
  ii-i'3] 
  of 
  this 
  pe- 
  

   culiar 
  form 
  for 
  comparison 
  with 
  the 
  form 
  here 
  referred 
  to 
  that 
  

   genus. 
  It 
  will 
  be 
  seen 
  from 
  the 
  second 
  figure 
  that 
  the 
  branchlets 
  

   may 
  bifurcate 
  again. 
  

  

  Chaetocladus 
  sardesoni 
  sp. 
  nov. 
  

  

  Plate 
  2, 
  figures 
  3-1 
  1 
  

  

  Professor 
  Sardeson 
  sent 
  me 
  some 
  years 
  ago 
  a 
  piece 
  of 
  magnesian 
  

   limestone 
  from 
  the 
  Bellerophon 
  bed 
  (Trenton-Galena 
  bed 
  2 
  of 
  his 
  

  

  