﻿28 
  INTEODUCTION. 
  

  

  esciilenta 
  feebly 
  pigmented; 
  and 
  of 
  black 
  tadpoles, 
  

   or 
  of 
  a 
  dark 
  brown 
  approaching 
  black, 
  I 
  only 
  know 
  

   Bufo 
  and 
  Bana 
  temp 
  or 
  aria 
  ; 
  all 
  the 
  other 
  European 
  

   species 
  are 
  only 
  exceptionally, 
  not 
  normally 
  very 
  dark. 
  

   That 
  the 
  light 
  cannot 
  have 
  a 
  great 
  effect 
  in 
  producing 
  

   the 
  pigment 
  in 
  Batrachian 
  larvse 
  is 
  shown 
  by 
  Ahjtes 
  

   and 
  Bomhinator, 
  both 
  of 
  which 
  develop 
  the 
  same 
  

   amount 
  of 
  pigmentation, 
  the 
  one 
  under 
  paternal 
  care 
  

   never 
  being 
  exposed 
  to 
  daylight, 
  the 
  other 
  reared 
  in 
  

   pools 
  or 
  puddles 
  exposed 
  to 
  the 
  full 
  action 
  of 
  the 
  sun's 
  

   rays. 
  

  

  Cases 
  of 
  melanism, 
  or 
  better, 
  absence 
  of 
  iridocytes 
  

   and 
  all 
  pigment 
  but 
  the 
  brown 
  or 
  black, 
  which 
  may 
  be 
  

   very 
  abundantly 
  and 
  exclusively 
  present, 
  have 
  been 
  

   observed 
  by 
  Heron-Roy 
  er 
  in 
  Alijtes 
  ohstetricans, 
  by 
  

   Alfred 
  Duges, 
  and 
  more 
  recently 
  by 
  Heron-Roy 
  er 
  and 
  

   by 
  Vaillant, 
  in 
  Bana 
  esciilenta. 
  I 
  found 
  a 
  similar 
  

   young 
  specimen 
  of 
  the 
  latter 
  species 
  in 
  a 
  marsh 
  near 
  

   the 
  Belgian 
  coast 
  in 
  1884 
  ; 
  the 
  back 
  was 
  brown, 
  

   nearly 
  black, 
  the 
  hinder 
  side 
  of 
  the 
  thighs 
  and 
  the 
  

   ventral 
  surface 
  pigmentless, 
  transparent 
  flesh-colour, 
  

   the 
  iris 
  black 
  without 
  any 
  gold. 
  A 
  male 
  specimen 
  of 
  

   Bana, 
  grxca 
  from 
  Italy, 
  showing 
  the 
  same 
  abnormality 
  

   in 
  the 
  absence 
  of 
  all 
  but 
  the 
  brown 
  colour, 
  was 
  sent 
  

   to 
  me 
  last 
  spring 
  by 
  Count 
  Peracca, 
  and 
  is 
  figured 
  on 
  

   Plate 
  XXII 
  of 
  this 
  work. 
  

  

  Albinism, 
  or 
  absence 
  of 
  the 
  brown 
  pigment, 
  on 
  the 
  

   other 
  hand, 
  has 
  been 
  observed 
  in 
  a 
  young 
  Bomhinator 
  

   pachj/jms 
  by 
  Fatio, 
  in 
  larvge 
  of 
  Alijtes 
  obstetricans 
  by 
  

   Lataste 
  and 
  Heron-Royer, 
  who 
  succeeded 
  in 
  rearing 
  

   them 
  through 
  the 
  metamorphosis, 
  in 
  a 
  larva 
  of 
  Disco- 
  

   glossus 
  pictus 
  by 
  myself, 
  in 
  Bana 
  esciilenta 
  by 
  Pavesi, 
  

   in 
  larvae 
  and 
  young 
  of 
  Bufo 
  viridis 
  by 
  Born, 
  Camerano, 
  

   and 
  myself, 
  in 
  larvae 
  of 
  Bana 
  temporaria 
  by 
  Lessona, 
  

   Fischer-Sigwart, 
  and 
  Camerano 
  ; 
  an 
  adult 
  female 
  of 
  

   the 
  latter 
  species 
  found 
  in 
  England 
  was 
  exhibited 
  

   alive 
  by 
  Mr. 
  Rowland 
  Ward 
  at 
  the 
  Linnean 
  Society 
  

   in 
  1891, 
  and 
  another, 
  from 
  Wiltshire, 
  presented 
  by 
  

   Mr. 
  W. 
  Hannaford, 
  is 
  now 
  preserved 
  in 
  the 
  British 
  

  

  