﻿SIMROTII 
  : 
  0>' 
  THE 
  AKAXOMV 
  OF 
  .NERlTIDiE. 
  33 
  

  

  forming 
  spermatophores,^ 
  is 
  Neritina, 
  but 
  even 
  the 
  most 
  northern 
  

   living 
  species, 
  N.fliiviatilis, 
  is 
  at 
  the 
  present 
  time 
  invading 
  the 
  sea 
  

   in 
  the 
  Baltic 
  on 
  its 
  northern 
  confines 
  under 
  the 
  swinging 
  circle. 
  

  

  ^ 
  I 
  consider 
  the 
  transferring 
  of 
  the 
  sperm 
  by 
  one 
  sperniatophore 
  of 
  the 
  Pulmonata 
  as 
  

   the 
  primary 
  state, 
  and 
  the 
  several 
  spermatophores 
  of 
  Nerita 
  as 
  the 
  secondary. 
  

   Here 
  it 
  could 
  be 
  objected 
  that 
  the 
  Cephalopoda 
  in 
  copulation 
  behave 
  in 
  the 
  same 
  

   manner 
  as 
  Ntrita. 
  But 
  I 
  should 
  remark 
  that 
  I 
  have 
  tried 
  to 
  derive 
  also 
  the 
  

   Cephalopoda 
  from 
  an 
  old 
  terrestrial 
  Pulmonate 
  stock. 
  The 
  paliBontological 
  

   appearance 
  of 
  the 
  different 
  Cephalopoda 
  groups 
  is 
  in 
  full 
  agreement 
  with 
  the 
  

   pendulation 
  theory. 
  

  

  VOL. 
  IX. 
  — 
  MARCH, 
  1910. 
  

  

  