﻿66 
  INTRODUCTION. 
  

  

  former 
  (inhabiting 
  the 
  extreme 
  south) 
  from 
  January 
  

   to 
  October, 
  the 
  latter 
  from 
  the 
  end 
  of 
  February 
  or 
  

   beginning 
  of 
  March 
  to 
  the 
  beginning 
  of 
  September. 
  

  

  The 
  time 
  at 
  which 
  each 
  species 
  commences 
  to 
  pair 
  

   varies, 
  as 
  we 
  have 
  seen, 
  with 
  the 
  temperature, 
  for 
  the 
  

   early 
  breeders 
  at 
  least. 
  Thus 
  in 
  the 
  south 
  of 
  Europe 
  

   these 
  would 
  start 
  from 
  January, 
  whilst 
  in 
  the 
  north 
  or 
  

   at 
  corresponding 
  altitudes 
  in 
  the 
  mountains 
  represen- 
  

   tatives 
  of 
  the 
  same 
  species 
  would 
  be 
  compelled 
  to 
  wait 
  

   until 
  the 
  thaw 
  has 
  set' 
  in. 
  Again, 
  exceptionally 
  pro- 
  

   longed 
  winters 
  may 
  cause 
  the 
  individuals 
  of 
  a 
  species 
  

   to 
  be 
  retarded 
  in 
  this 
  operation, 
  so 
  as 
  to 
  bring 
  them 
  

   together 
  with 
  others 
  which, 
  under 
  normal 
  circum- 
  

   stances, 
  do 
  not 
  breed 
  until 
  some 
  weeks 
  later. 
  But, 
  

   on 
  the 
  whole, 
  our 
  Batrachians 
  may 
  be 
  arranged 
  in 
  the 
  

   following 
  order, 
  beginning 
  with 
  the 
  most 
  precocious 
  : 
  

  

  1. 
  Discoglossiis, 
  Rana 
  temfovaria, 
  B. 
  arvalis. 
  

  

  2. 
  Rana 
  agilis, 
  Ahjtes. 
  

  

  3. 
  Bufo 
  vulgaris, 
  PeJohates, 
  Pelodytes. 
  

  

  4. 
  Bufo 
  viridis, 
  Bufo 
  calamita, 
  Hijla, 
  Bomhinator, 
  

  

  Rana 
  esculenta. 
  

  

  Taking 
  the 
  three 
  British 
  species 
  as 
  an 
  example, 
  

   Rana 
  temporaria 
  in 
  normal 
  years 
  with 
  us 
  breeds 
  in 
  

   the 
  beginning 
  of 
  March, 
  Bufo 
  vulgaris 
  in 
  the 
  beginning 
  

   of 
  April, 
  and 
  Bufo 
  calamita 
  from 
  the 
  middle 
  of 
  May 
  ; 
  

   their 
  nuptial 
  periods 
  do 
  not 
  even 
  overlap. 
  

  

  Leaving 
  out 
  the 
  genus 
  Alytes, 
  which 
  is 
  altogether 
  

   exceptional 
  in 
  its 
  mode 
  of 
  parturition, 
  all 
  our 
  Batra- 
  

   chians 
  are 
  compelled 
  to 
  resort 
  to 
  the 
  water 
  for 
  the 
  

   purpose 
  of 
  depositing 
  their 
  spawn. 
  In 
  some 
  species, 
  

   such 
  as 
  our 
  common 
  frog, 
  the 
  males 
  precede 
  the 
  

   females, 
  and 
  may 
  be 
  found 
  in 
  winter 
  in 
  a 
  semi-torpid 
  

   condition, 
  but 
  already 
  attired 
  in 
  their 
  full 
  breeding 
  

   costume, 
  at 
  the 
  bottom 
  of 
  pools 
  thickly 
  coated 
  with 
  

   ice. 
  The 
  common 
  toad 
  travels 
  long 
  distances 
  on 
  land, 
  

   or 
  following 
  the 
  course 
  of 
  brooks, 
  in 
  quest 
  of 
  suitable 
  

   breeding- 
  places 
  ; 
  and 
  if 
  the 
  sexes 
  meet 
  on 
  the 
  way 
  the 
  

   male 
  often 
  secures 
  immediate 
  possession 
  of 
  the 
  female, 
  

   accomplishing 
  the 
  rest 
  of 
  the 
  journey 
  on 
  her 
  back. 
  

  

  