﻿6G4 
  rROCEEBINGS 
  or 
  THE 
  XATTOXAL 
  MUSEUM. 
  

  

  tion 
  was 
  inoperative, 
  because 
  lie 
  bad 
  been 
  forestalled 
  by 
  an 
  earlier 
  

   writer. 
  J. 
  C. 
  Fabricius, 
  in 
  bis 
  various 
  writings, 
  of 
  wliicb 
  it 
  will 
  be 
  

   sutticient 
  to 
  cite 
  tlie 
  'Species 
  Tnsectoruni,' 
  1781, 
  and 
  the 
  'Entomologia 
  

   Systeniatica,' 
  1703, 
  consistently 
  places 
  Asiacns 
  marlmis 
  {Cancer 
  (jam- 
  

   marus 
  Linnaeus) 
  as 
  tbe 
  first 
  species 
  of 
  the 
  genus 
  Astaeus, 
  giving 
  to 
  

   A. 
  J^uviaiUis 
  invariably 
  the 
  second 
  jdace. 
  Tbere 
  can 
  therefore 
  be 
  no 
  

   reasonable 
  gainsaying 
  that 
  he 
  made 
  the 
  European 
  lobster, 
  and 
  not 
  

   the 
  river 
  crayfish, 
  the 
  type. 
  I'roni 
  this 
  it 
  follows 
  * 
  * 
  * 
  that 
  the 
  

   generic 
  name 
  of 
  the 
  lobster 
  is 
  properly 
  ^Istocws, 
  and 
  that 
  of 
  the 
  Euro- 
  

   pean 
  crayfish 
  Fotamohiusy 
  

  

  It 
  is 
  hard 
  to 
  believe 
  that 
  this 
  contention 
  of 
  Mr. 
  Stebbing's 
  is 
  made 
  

   in 
  good 
  faith, 
  involving 
  as 
  it 
  does 
  an 
  unreasonable 
  and 
  long-discarded 
  

   method 
  of 
  ascertaining 
  a 
  type. 
  Such 
  a 
  method 
  is 
  repudiated 
  every 
  time 
  

   we 
  concede 
  to 
  an 
  author 
  who 
  first 
  subdivides 
  a 
  genus 
  in 
  which 
  no 
  type 
  

   has 
  been 
  specified, 
  the 
  right 
  to 
  restrict 
  the 
  original 
  name 
  to 
  sucli 
  part 
  

   of 
  it 
  as 
  he 
  jdeases. 
  It 
  is 
  not 
  true 
  that 
  the 
  first 
  species 
  is 
  presumably 
  

   the 
  author's 
  implied 
  tyi)e. 
  Fabricius's 
  genus 
  Astacus 
  was 
  formed 
  by 
  a 
  

   dismemberment 
  of 
  the 
  genus 
  Cancer 
  of 
  Linnanis, 
  and 
  the 
  sequenc(^ 
  of 
  

   the 
  two 
  species 
  under 
  consideration 
  in 
  Fabricius's 
  works 
  was 
  undoubt- 
  

   edly 
  derived 
  from 
  the 
  "Systema 
  Natura'," 
  where 
  (in 
  the 
  twelfth 
  edition) 
  

   Cancer 
  gammarus 
  stands 
  as 
  No. 
  62, 
  Cancer 
  astacus 
  as 
  No. 
  03, 
  in 
  the 
  

   genus 
  Cancer. 
  A 
  better, 
  though 
  not 
  a 
  valid, 
  claim 
  might 
  be 
  set 
  up 
  for 
  

   A. 
  fiuinatilis 
  as 
  Fabricius's 
  implied 
  type 
  of 
  his 
  genus 
  Astacns^ 
  since 
  

   that 
  species 
  is 
  the 
  Cancer 
  astacus 
  of 
  Linna'us. 
  

  

  In 
  Agassiz's 
  '•'Nomenclator 
  Zoologicus" 
  the 
  name 
  Potamoh'ms 
  is 
  

   entered 
  as 
  a 
  genus 
  of 
  Brachyura, 
  with 
  a 
  citation 
  of 
  Leach's 
  article 
  in 
  

   "Dictionnaire 
  des 
  Sciences 
  Naturelles," 
  XII, 
  1818. 
  By 
  reference 
  to 
  

   this 
  work 
  it 
  apj)ears 
  that 
  the 
  name 
  occurs 
  on 
  page 
  75, 
  under 
  the 
  Galli- 
  

   cized 
  form 
  " 
  Potamobie," 
  in 
  a 
  merely 
  nominal, 
  alphabetical 
  list 
  of 
  the 
  

   genera 
  of 
  Crustacea, 
  Since 
  the 
  crayfish 
  and 
  lobster 
  are 
  both 
  entered 
  

   elsewhere 
  in 
  the 
  same 
  list, 
  by 
  the 
  names 
  of 
  " 
  Ecrevisse'' 
  and 
  " 
  Ilomard," 
  

   I 
  am 
  inclined 
  to 
  think 
  that 
  " 
  Potamobie" 
  was 
  here 
  really 
  intended 
  for 
  a 
  

   genus 
  of 
  fluviatile 
  crabs, 
  as 
  assumed 
  in 
  the 
  " 
  Nomenclator," 
  and 
  that 
  it 
  

   was 
  written 
  through 
  a 
  lapsns 
  pennw 
  for 
  " 
  Potamophile," 
  i. 
  e., 
  Potamo- 
  

   pMlus 
  or 
  Fotamon. 
  As 
  the 
  name 
  occurs 
  as 
  a 
  pure 
  nomen 
  nudum 
  in 
  the 
  

   " 
  Dictionnaire," 
  it 
  would 
  be 
  unworthy 
  of 
  notice 
  but 
  for 
  the 
  fact 
  that 
  

   Desmarest 
  said 
  in 
  1823:^ 
  "II 
  est 
  probable 
  que 
  ce 
  genre 
  [Thelphusa 
  on 
  

   Potamophilns] 
  differe 
  pen, 
  on 
  ne 
  diflfere 
  pas 
  de 
  ceux 
  qui 
  ont 
  ^te 
  nommes 
  

   Potamon 
  par 
  M. 
  Savigny, 
  et 
  Potamobia 
  par 
  M. 
  Leach," 
  and 
  that 
  Eisso 
  

   in 
  1826^ 
  adopted 
  ^^ 
  Potamohins 
  Leach" 
  (with 
  '' 
  Potamophile" 
  as 
  the 
  

   French 
  equivalent) 
  as 
  the 
  generic 
  name 
  for 
  the 
  fresh 
  water 
  crab, 
  Potamon 
  

   Jluviatilis. 
  In 
  this 
  way, 
  i^robably, 
  it 
  came 
  to 
  pass 
  that 
  Huxley^ 
  was 
  

   led 
  into 
  the 
  essentially 
  erroneous 
  assertion 
  that 
  Potamohhis 
  had 
  been 
  

   used 
  in 
  another 
  sense 
  before 
  it 
  was 
  applied 
  to 
  the 
  crayfish. 
  

  

  1 
  Dictionnaire 
  des 
  Sciences 
  Naturelles, 
  XXVIII, 
  p. 
  246. 
  

   ^Hist. 
  Nat. 
  (le 
  I'Enrope 
  M^rid., 
  Y, 
  p. 
  14. 
  

   sproc. 
  Zool. 
  Soc. 
  Loudon, 
  1878, 
  p. 
  752. 
  

  

  