﻿COOKE: 
  ON 
  PATELLA 
  VULGATA 
  AKD 
  P. 
  DEPRESSA. 
  137 
  

  

  form, 
  and 
  that 
  while 
  the 
  northern 
  limit 
  of 
  the 
  distribution 
  of 
  vulgata 
  

   is 
  about 
  the 
  latitude 
  of 
  the 
  Lofoden 
  Islands, 
  that 
  of 
  depressa 
  is 
  very 
  

   much 
  farther 
  south. 
  

  

  It 
  should 
  be 
  made 
  clear 
  that 
  the 
  statement 
  of 
  Forbes 
  & 
  Hanley 
  — 
  

   the 
  two 
  forms 
  " 
  inhabit 
  different 
  levels, 
  the 
  vulgata 
  being 
  always 
  in 
  

   the 
  higher 
  zone 
  " 
  — 
  does 
  not 
  represent 
  the 
  facts 
  accurately. 
  P. 
  vtilgata, 
  

   as 
  is 
  well 
  known, 
  lives 
  from 
  near 
  high-water 
  mark 
  to 
  the 
  extreme 
  of 
  

   low-water. 
  P. 
  dejyressa, 
  on 
  the 
  other 
  hand, 
  is 
  seldom 
  found 
  till 
  near 
  

   low-water 
  mark, 
  where, 
  so 
  far 
  as 
  my 
  experience 
  goes, 
  vulgata 
  and 
  

   depressa 
  occur 
  abundantly 
  on 
  the 
  same 
  masses 
  of 
  rock. 
  This 
  fact 
  

   further 
  strengthens 
  the 
  case 
  for 
  their 
  specific 
  difference. 
  

  

  *j^* 
  Since 
  the 
  foregoing 
  paper 
  was 
  read, 
  our 
  Editor 
  informs 
  me 
  that 
  

   it 
  is 
  stated 
  in 
  Woodward's 
  Manual, 
  1st 
  ed., 
  p. 
  451, 
  that 
  " 
  Mr. 
  Wilton 
  

   has 
  ascertained 
  that 
  Patella 
  athletica 
  may 
  be 
  distinguished 
  from 
  the 
  

   common 
  limpet 
  of 
  our 
  coast 
  by 
  its 
  teeth". 
  He 
  further 
  tells 
  me 
  that 
  

   in 
  his 
  uncle's 
  interleaved 
  working 
  copy 
  of 
  the 
  Manual, 
  now 
  in 
  his 
  

   possession, 
  he 
  finds 
  the 
  following 
  manuscript 
  note 
  : 
  " 
  Patella 
  athletica 
  : 
  

   dental 
  canal 
  not 
  much 
  longer 
  than 
  the 
  shell 
  (scarcely 
  half 
  as 
  long 
  as 
  

   in 
  P. 
  vulgata) 
  : 
  teeth 
  closer 
  together 
  than 
  in 
  P. 
  vulgata 
  ; 
  more 
  

   massive 
  and 
  with 
  shorter 
  cusps 
  ; 
  the 
  difference 
  is 
  greater 
  in 
  the 
  

   imperfectly 
  developed 
  teeth 
  near 
  the 
  further 
  extremity 
  of 
  the 
  canal." 
  

  

  