﻿FIFTH 
  REPORT 
  OF 
  THE 
  DIRECTOR 
  I908 
  I95 
  

  

  son 
  and 
  Etheridge 
  from 
  the 
  Lower 
  Siluric 
  of 
  Ayrshire, 
  England, 
  

   placing 
  it 
  with 
  some 
  doubt 
  among 
  the 
  Codiaceae 
  to 
  which 
  he 
  also 
  

   referred 
  the 
  Mesozoic 
  Sphaerocodium. 
  Both 
  Girvanella 
  and 
  

   Sphaerocodimn 
  form 
  compact 
  bodies 
  essentially 
  composed 
  of 
  an 
  in- 
  

   tricate 
  mass 
  of 
  fine 
  continuous 
  tubes. 
  Alexander 
  Brown 
  next 
  took 
  

   up 
  the 
  problem 
  of 
  the 
  taxonomic 
  position 
  of 
  Solenopora,^ 
  a 
  genus 
  

   that 
  in 
  Solenopora 
  com 
  pacta 
  (Billings) 
  , 
  its 
  genotype, 
  is 
  

   well 
  represented 
  in 
  the 
  Lower 
  Siluric 
  of 
  New 
  York, 
  and 
  discov- 
  

   ered 
  its 
  cellular 
  structure 
  (a 
  tubular 
  one 
  was 
  assumed 
  before), 
  

   finding 
  that 
  its 
  cells 
  bear 
  great 
  similarity 
  to 
  those 
  of 
  certain 
  living 
  

   and 
  fossil 
  coralline 
  algae 
  and 
  that 
  there 
  are 
  also 
  traces 
  of 
  tetra- 
  

   sporangia 
  and 
  conceptacles 
  corresponding 
  to 
  those 
  of 
  the 
  recent 
  

   Corallineae,.to 
  which 
  he 
  therefore 
  refers 
  Solenopora 
  as 
  a 
  possible 
  

   ancestor 
  of 
  the 
  recent 
  nullipores.^ 
  

  

  E. 
  Stolley^ 
  in 
  1893 
  demonstrated 
  the 
  presence 
  of 
  indubitable 
  

   calcareous 
  algae 
  in 
  boulders 
  of 
  northern 
  Germany 
  derived 
  from 
  

   the 
  Lower 
  Siluric 
  of 
  Sweden 
  and 
  described 
  a 
  number 
  of 
  forms 
  

   which 
  exhibit 
  relationship 
  to 
  the 
  recent 
  Bornetella 
  and 
  the 
  triassic 
  

   Gyroporella, 
  and 
  all 
  of 
  which 
  were 
  undoubtedly 
  verticillate 
  Si- 
  

   phoneae 
  except 
  one 
  (Arthroporella 
  eaten 
  ularia) 
  wdiich 
  

   consists 
  of 
  chains 
  of 
  spheric 
  and 
  pear-shaped 
  bodies 
  and 
  is 
  com- 
  

   pared 
  with 
  the 
  Eocene 
  Ovulites. 
  

  

  Finally, 
  Whitfield* 
  placed 
  a 
  form 
  hitherto 
  referred 
  to 
  the 
  grapto- 
  

   lites 
  (Bythograptus 
  lax 
  us) 
  among 
  the 
  algae, 
  principally 
  

   for 
  the 
  reason 
  that 
  the 
  secondary 
  branbhes 
  are 
  connected 
  by 
  distinct 
  

   articulations 
  with 
  the 
  central 
  stipe 
  and 
  that 
  proper 
  cell 
  apertures 
  

   are 
  absent 
  or 
  indistinguishable. 
  

  

  ^ 
  Brown, 
  Alexander. 
  On 
  the 
  Structure 
  and 
  Affinities 
  of 
  the 
  Genus 
  

   Solenopora. 
  Geol. 
  Mag. 
  IV. 
  1894. 
  p. 
  145. 
  

  

  ^ 
  Professor 
  Rothpletz 
  has 
  lately 
  published 
  the 
  results 
  of 
  his 
  most 
  thorough 
  

   and 
  painstaking 
  investigations 
  of 
  these 
  difficult 
  and 
  problematic 
  forms 
  [see 
  

   Ueber 
  Algen 
  und 
  Hydrozoen 
  im 
  Silur 
  von 
  Gotland 
  und 
  Oesel, 
  in 
  Kongl. 
  

   Svenska 
  Vetensk. 
  Handl. 
  Bd. 
  43, 
  no. 
  5, 
  1908] 
  positively 
  placing 
  Gir- 
  

   vanella 
  problematica, 
  and 
  Sphaerocodium, 
  to 
  which 
  also 
  a 
  Siluric 
  

   form 
  is 
  referred, 
  as 
  well 
  as 
  Solenopora, 
  among 
  the 
  algae. 
  As 
  most 
  important 
  

   for 
  the 
  taxonomic 
  position 
  of 
  Solenopora, 
  he 
  considers 
  the 
  presence 
  of 
  

   perforations 
  of 
  the 
  cell 
  walls 
  discovered 
  by 
  him, 
  the 
  arrangement 
  of 
  the 
  con- 
  

   centric 
  rows 
  of 
  cells 
  and 
  the 
  similarity 
  of 
  the 
  tubular, 
  isolated 
  sporangia 
  in 
  

   Solenopora 
  gotlandica 
  and 
  the 
  Archaeolithothamnia. 
  

  

  In 
  a 
  review 
  by 
  Steinmann 
  (Zeitschr. 
  fijr 
  Induktive 
  Abstammungs-und 
  

   Vererbungslclire, 
  Bd. 
  i, 
  Hft. 
  4, 
  p. 
  405, 
  1909) 
  that 
  has 
  just 
  come 
  to 
  hand 
  the 
  

   existence 
  of 
  probable 
  transitional 
  forms 
  (in 
  the 
  Permian 
  Hmestoncs 
  of 
  Sicily 
  

   and 
  the 
  Jurassic) 
  between 
  the 
  Siluric 
  Solenopora 
  and 
  Lithothamnium, 
  that 
  

   begins 
  in 
  the 
  Cretaceous 
  period, 
  is 
  pointed 
  out. 
  

  

  'Ueber 
  silurische 
  Siphoneen. 
  Neues 
  Jahrbuch 
  1893. 
  2:135. 
  

  

  * 
  Whitfield, 
  R. 
  P. 
  On 
  New 
  Forms 
  of 
  Marine 
  Algae 
  from 
  the 
  Trenton 
  

   Limestone, 
  with 
  Observations 
  on 
  Bythograptus 
  lax 
  us 
  Hall. 
  Bui. 
  

   Am. 
  Mus. 
  Nat. 
  Hist. 
  1894. 
  v. 
  6, 
  art. 
  16, 
  p. 
  351. 
  

  

  