﻿326 
  FRANCIS 
  H. 
  A. 
  MARSHALL. 
  

  

  absence 
  of 
  the 
  male, 
  the 
  duration 
  of 
  the 
  dicestrous 
  cycle 
  being 
  

   about 
  a 
  month, 
  there 
  being 
  also 
  a 
  longer 
  anoestrous 
  period. 
  

  

  Bell 
  (1874) 
  describes 
  the 
  otter 
  as 
  having 
  young 
  in 
  March 
  

   or 
  April, 
  thus 
  indicating 
  that 
  the 
  wild 
  otter 
  has 
  a 
  single 
  sexual 
  

   season 
  about 
  the 
  beginning 
  of 
  the 
  year. 
  The 
  same 
  author 
  

   states 
  that 
  the 
  progeny 
  of 
  the 
  stoat 
  are 
  produced 
  in 
  April 
  or 
  

   May, 
  while 
  the 
  polecat, 
  of 
  which 
  the 
  ferret 
  is 
  a 
  domesticated 
  

   variety, 
  is 
  said 
  to 
  give 
  birth 
  to 
  young 
  in 
  May 
  or 
  June. 
  These 
  

   animals, 
  therefore, 
  are 
  probably 
  monoestrous, 
  or 
  perhaps 
  

   dioestrous, 
  while 
  the 
  weasel 
  may 
  perhaps 
  be 
  inferred 
  to 
  be 
  

   polycestrous 
  from 
  Bell's 
  account 
  (1874). 
  

  

  With 
  the 
  pine-marten, 
  in 
  captivity, 
  it 
  appears 
  from 
  Cocks' 
  

   description 
  (1900) 
  that 
  the 
  oestrous 
  period 
  may 
  extend 
  to 
  about 
  

   a 
  fortnight. 
  A 
  female 
  was 
  noticed 
  to 
  deposit 
  here 
  and 
  there 
  

   in 
  her 
  cage 
  little 
  mouthfuls 
  of 
  straw, 
  an 
  indication 
  of 
  her 
  

   being 
  in 
  season, 
  this 
  habit 
  having 
  been 
  previously 
  observed 
  

   in 
  the 
  case 
  of 
  the 
  otter. 
  A 
  male 
  was 
  admitted 
  on 
  January 
  5th, 
  

   shut 
  off 
  on 
  the 
  16th, 
  readmitted 
  on 
  the 
  17th, 
  and 
  finally 
  

   separated 
  on 
  the 
  18th. 
  Copulation 
  is 
  supposed 
  to 
  have 
  

   occurred 
  probably 
  on 
  the 
  8th, 
  10th, 
  and 
  13th, 
  and 
  possibly 
  

   also 
  at 
  other 
  times, 
  but 
  was 
  never 
  actually 
  observed. 
  Young 
  

   were 
  produced 
  on 
  April 
  22nd. 
  Cocks 
  states 
  that 
  it 
  is 
  

   hazardous 
  to 
  allow 
  the 
  male 
  and 
  female 
  to 
  run 
  together 
  at 
  

   other 
  times 
  than 
  the 
  oestrous 
  period, 
  as 
  it 
  is 
  apt 
  to 
  result 
  in 
  

   the 
  death 
  of 
  the 
  female. 
  

  

  The 
  badger 
  is 
  probably 
  monoestrous, 
  with 
  an 
  annual 
  sexual 
  

   season, 
  its 
  period 
  of 
  gestation 
  being 
  between 
  four 
  and 
  five 
  

   months 
  (Meade-Waldo, 
  1894). 
  (See 
  postscript 
  at 
  end 
  of 
  

   paper.) 
  

  

  I 
  made 
  no 
  observations 
  on 
  the 
  length 
  of 
  the 
  ferret's 
  gesta- 
  

   tion, 
  but 
  this 
  period 
  is 
  generally 
  stated 
  to 
  be 
  about 
  six 
  weeks, 
  

   or 
  approximately 
  the 
  same 
  as 
  that 
  observed 
  for 
  the 
  polecat 
  

   (Harting, 
  1891; 
  Cocks, 
  1891). 
  

  

  External 
  Evidence 
  of 
  the 
  Pro-oestrum 
  and 
  ffistrus. 
  

   — 
  The 
  pro-oestrum 
  with 
  the 
  female 
  ferret 
  appears 
  to 
  extend 
  

   for 
  about 
  three 
  weeks, 
  and 
  is 
  characterised 
  by 
  a 
  marked 
  

   swelling 
  of 
  the 
  vulva 
  and 
  a 
  sanguineo-mucous 
  flow. 
  With 
  

  

  