﻿Geology. 
  305 
  

  

  II. 
  Geology 
  

  

  1. 
  Factors 
  of 
  Climatic 
  Control; 
  by 
  W. 
  J. 
  Humphreys. 
  

   Jour. 
  Franklin 
  Inst,, 
  188, 
  775-810, 
  1919 
  ; 
  189, 
  63-98, 
  1920.— 
  This 
  

   very 
  important 
  paper 
  on 
  the 
  factors 
  that 
  control 
  climates 
  of 
  the 
  

   present 
  and 
  past 
  should 
  be 
  read 
  by 
  all 
  geologists 
  and 
  paleon- 
  

   tologists. 
  The 
  factors 
  discussed 
  number 
  fourteen, 
  and 
  of 
  these 
  

   the 
  following 
  are 
  the 
  most 
  important: 
  (7) 
  Extent 
  and 
  compo- 
  

   sition 
  of 
  the 
  atmosphere, 
  (8) 
  Vulcanism, 
  (10) 
  Land 
  elevation, 
  

   (11) 
  Land 
  and 
  water 
  distribution, 
  (12) 
  Atmospheric 
  circula- 
  

   tion, 
  (13) 
  Oceanic 
  circulation, 
  and 
  (14) 
  Surface 
  covering. 
  The 
  

   factors 
  mentioned, 
  when 
  most 
  significant, 
  are 
  thought 
  to 
  bring 
  

   on 
  the 
  glacial 
  climates. 
  Volcanic 
  ash 
  floating 
  high 
  above 
  the 
  

   zone 
  of 
  clouds 
  is 
  believed 
  to 
  be 
  a 
  contributing 
  cause 
  of 
  much 
  

   significance 
  in 
  glacial 
  climates, 
  and 
  its 
  absence 
  the 
  reason 
  for 
  

   the 
  warmer 
  interglacial 
  conditions. 
  c. 
  s. 
  

  

  2. 
  JJeber 
  fraglicke 
  Tunicaten 
  aus 
  dem 
  Perm 
  Siciliens; 
  

   Palaeont. 
  Zeits., 
  2, 
  66-74, 
  1 
  pi., 
  2 
  text 
  figs., 
  1915. 
  Ueber 
  die 
  

   Organization 
  der 
  Anthozoen; 
  Ibid., 
  2, 
  232-250, 
  14 
  text 
  figs,, 
  

   1918. 
  Phylogenie 
  und 
  System 
  der 
  Pelmatozoen; 
  Ibid., 
  3, 
  1-128, 
  

   114 
  text 
  figs., 
  1918. 
  By 
  Otto 
  Jaekel. 
  — 
  In 
  the 
  first 
  paper 
  cited, 
  

   Jaekel 
  describes 
  some 
  small 
  fossils 
  that 
  occur 
  in 
  the 
  limestones 
  

   of 
  Sosio, 
  Sicily, 
  as 
  natural 
  molds. 
  These 
  he 
  compares 
  with 
  liv- 
  

   ing 
  tunicates 
  of 
  the 
  genus 
  Rhodosoma, 
  to 
  which 
  they 
  have 
  con- 
  

   siderable 
  likeness. 
  However, 
  no 
  pyramids 
  closing 
  the 
  two 
  

   openings 
  into 
  the 
  sack, 
  as 
  in 
  living 
  forms, 
  have 
  as 
  yet 
  been 
  found 
  

   in 
  these 
  fossils. 
  For 
  this 
  reason 
  the 
  form 
  Permosoma 
  tunicatum, 
  

   n. 
  gen. 
  et 
  sp., 
  is 
  doubtfully 
  referred 
  to 
  the 
  solitary 
  tunicates. 
  

  

  In 
  the 
  second 
  paper, 
  which 
  is 
  of 
  a 
  highly 
  theoretic 
  nature, 
  the 
  

   author 
  takes 
  up 
  an 
  ontogenetic 
  study 
  of 
  the 
  septal 
  introduction 
  

   in 
  the 
  Tetracoralla 
  and 
  Hexacoralla, 
  and 
  concludes 
  from 
  this 
  

   and 
  other 
  evidence 
  that 
  the 
  Anthozoa 
  had 
  their 
  origin 
  in 
  a 
  

   bilaterally 
  symmetrical, 
  errant 
  and 
  metameric, 
  worm-like 
  ani- 
  

   mal, 
  with 
  a 
  mouth 
  at 
  one 
  end 
  and 
  an 
  anus 
  at 
  the 
  other 
  end 
  of 
  a 
  

   digestive 
  tract. 
  This 
  form 
  adapted 
  itself 
  through 
  fixation 
  to 
  a 
  

   sessile 
  mode 
  of 
  life, 
  which 
  caused 
  it 
  to 
  bend 
  and 
  double 
  on 
  itself, 
  

   bringing 
  the 
  polar 
  ends 
  into 
  close 
  association. 
  A 
  new 
  mouth 
  

   was 
  eventually 
  developed 
  in 
  what 
  was 
  originally 
  the 
  posterior 
  

   end, 
  and 
  the 
  original 
  mouth, 
  gut, 
  and 
  anus 
  transformed 
  into 
  the 
  

   simplified 
  gastral 
  cavity 
  of 
  these 
  sack-like 
  animals. 
  Accord- 
  

   ingly, 
  the 
  Anthozoa 
  arose 
  in 
  a 
  stock 
  higher 
  in 
  development 
  than 
  

   the 
  assumed 
  planula. 
  

  

  The 
  third 
  paper 
  is 
  by 
  far 
  the 
  most 
  important 
  of 
  the 
  three 
  here 
  

   noticed. 
  It 
  is 
  twenty 
  years 
  since 
  Jaekel 
  published 
  his 
  great 
  

   work 
  on 
  the 
  history 
  of 
  the 
  Pelmatozoa, 
  and 
  as 
  he 
  does 
  not 
  now 
  

   see 
  his 
  way 
  to 
  a 
  completion 
  of 
  it 
  in 
  the 
  detailed 
  manner 
  of 
  the 
  

   first 
  volume, 
  he 
  here 
  gives 
  an 
  extended 
  sketch 
  of 
  his 
  ideas 
  as 
  to 
  

   the 
  interrelations 
  of 
  the 
  Echinoderma, 
  and 
  especially 
  the 
  stalked 
  

  

  