﻿398 
  On 
  Gammarus 
  campylops, 
  Leach. 
  

  

  published 
  1850, 
  follows 
  Samouelle's 
  ' 
  Entomologist's 
  Useful 
  

   Compendium' 
  in 
  calling 
  it 
  camptolops. 
  Milne-Edwards, 
  in 
  

   Ann. 
  Sci. 
  Nat. 
  vol. 
  xx. 
  (1830) 
  p. 
  367, 
  has 
  camphylops. 
  

   Its 
  next 
  appearance 
  of 
  any 
  importance 
  is 
  in 
  Spence 
  Bate's 
  

   ' 
  Catalogue 
  of 
  Amphipodous 
  Crustacea 
  in 
  the 
  Brit. 
  Mus.' 
  

   (1862) 
  as 
  camptolops, 
  but 
  the 
  same 
  author 
  in 
  1863 
  (Bate 
  & 
  

   Westwood, 
  ' 
  Brit. 
  Sess.-eyed 
  Crust.') 
  calls 
  it 
  campylops, 
  at 
  

   which 
  it 
  remained 
  till 
  the 
  revival 
  of 
  camylops 
  in 
  ' 
  Das 
  Tier- 
  

   reich' 
  (1906). 
  

  

  The 
  confusion 
  in 
  regard 
  to 
  the 
  description 
  of 
  the 
  animal 
  

   has 
  been 
  even 
  greater, 
  and 
  for 
  this 
  Leach 
  himself 
  was 
  largely 
  

   responsible. 
  His 
  first 
  notice 
  gives 
  practically 
  no 
  description 
  

   by 
  which 
  the 
  species 
  could 
  be 
  recognized, 
  except 
  the 
  S-like 
  

   eyes. 
  In 
  the 
  Trans. 
  Linn. 
  Soc. 
  /. 
  c. 
  he 
  divides 
  the 
  genus 
  

   Gammarus 
  as 
  follows 
  : 
  — 
  

  

  A. 
  Cauda 
  stylis 
  geminatis 
  super 
  ioribus 
  stylo 
  supero 
  brevissimo 
  

   (». 
  e. 
  Upper, 
  or 
  inner, 
  ramus 
  of 
  the 
  third 
  uropods 
  very 
  short). 
  

  

  Spec. 
  1. 
  Gammarus 
  aquaticus. 
  

  

  Gammarus 
  pulex, 
  Leach, 
  Edin. 
  Encycl. 
  vii. 
  402-32. 
  

  

  Habitat 
  iu 
  rivulis 
  et 
  stagnis 
  vulgatissima. 
  

  

  Spec. 
  2. 
  Gammarus 
  marinus. 
  

   Habitat 
  in 
  Danmoniae 
  australis 
  mari. 
  

  

  B. 
  Cauda 
  stylis 
  geminatis 
  superioribus 
  stylis 
  subaequalibus 
  

   (i. 
  e. 
  Rami 
  of 
  the 
  third 
  uropods 
  subequal). 
  

  

  Spec. 
  3. 
  Gammarus 
  Locusta. 
  

   G. 
  oculis 
  lunatis. 
  

  

  Cancer 
  Gammarus 
  Locusta, 
  Montagu, 
  Linn. 
  Trans, 
  ix. 
  92. 
  

   Habitat 
  in 
  Britanniae 
  mari 
  vulgatissime. 
  

  

  Spec. 
  4. 
  Gammarus 
  campylops. 
  

   G. 
  oculis 
  flexuosis. 
  

   Gammarus 
  campylops 
  (sic), 
  Leach, 
  Edin. 
  Encycl. 
  vii. 
  403. 
  

  

  Habitat 
  in 
  mari 
  prope 
  Loch-Ranza 
  in 
  Arran 
  Insula. 
  

  

  There 
  is 
  clearly 
  something 
  wrong 
  here 
  : 
  G. 
  aquaticus 
  (now 
  

   called 
  G. 
  pulex) 
  , 
  which, 
  as 
  the 
  common 
  freshwater 
  species, 
  

   cannot 
  be 
  mistaken, 
  has 
  the 
  rami 
  of 
  the 
  third 
  uropods 
  at 
  least 
  

   as 
  nearly 
  equal 
  as 
  G. 
  locusta, 
  yet 
  is 
  bracketed 
  with 
  G. 
  mari- 
  

   nus, 
  which 
  has 
  the 
  upper 
  or 
  inner 
  ramus 
  less 
  than 
  half 
  as 
  

   long 
  as 
  the 
  lower 
  or 
  outer 
  and 
  is 
  therefore 
  rightly 
  placed 
  in 
  

   the 
  first 
  group. 
  As 
  G. 
  locusta 
  is 
  correctly 
  placed 
  in 
  the 
  

   second 
  group, 
  it 
  follows 
  that, 
  in 
  all 
  probability, 
  G. 
  pulex 
  and 
  

   G. 
  campylops 
  have 
  been 
  transposed 
  and 
  that 
  the 
  latter 
  has 
  the 
  

   inner 
  ramus 
  very 
  short. 
  

  

  Fortunately 
  Leach's 
  original 
  specimens 
  (2) 
  from 
  the 
  Isle 
  

  

  