﻿NIAGARA 
  FALLS 
  AND 
  VICINITY 
  24I 
  

  

  Genus 
  amnicola 
  Gould 
  & 
  Haldeman. 
  1841 
  

  

  Shell 
  small, 
  short, 
  subglobular, 
  and 
  ovate; 
  spire 
  obtuse; 
  shell 
  

   smooth, 
  thin 
  and 
  perforate; 
  aperture 
  ovate; 
  lip 
  thin; 
  operculum 
  

   corneous. 
  

  

  Amnicola 
  limosa 
  (Say) 
  Hald. 
  1844. 
  Pal 
  u 
  din 
  a 
  limosa 
  

   Say 
  (1817. 
  Acad. 
  nat. 
  sci. 
  Phil. 
  Jour. 
  1:125). 
  Amnicola 
  

   limosa 
  Haldeman 
  (1844. 
  Monograph 
  pi. 
  i, 
  fig. 
  5, 
  6) 
  

  

  Shell 
  small 
  and 
  conic; 
  whorls 
  four, 
  rapidly 
  diminishing; 
  apex 
  

   acute, 
  suture 
  deep 
  ; 
  umbilicus 
  narrow 
  and 
  deep 
  ; 
  surface 
  smooth 
  ; 
  re- 
  

   cent 
  specimens 
  show 
  growth 
  lines 
  ; 
  aperture 
  oval, 
  slightly 
  angulated 
  

   at 
  the 
  junction 
  of 
  the 
  body 
  whorl; 
  lip 
  simple. 
  

  

  Found 
  in 
  the 
  gravel 
  pit 
  on 
  Goat 
  island. 
  

  

  Amnicola 
  letsoni 
  Walker 
  1901 
  (Fig. 
  165) 
  

  

  A. 
  letsoni 
  Walker 
  (Feb. 
  1901. 
  Nautilus) 
  

  

  Shell 
  small, 
  elevated 
  and 
  thick; 
  whorls 
  four 
  or 
  five, 
  more 
  or 
  less 
  

   flattened, 
  and 
  incHned 
  to 
  be 
  shouldered; 
  suture 
  deep; 
  

   spire 
  short, 
  less 
  than 
  one 
  third 
  the 
  entire 
  length; 
  apex 
  A 
  

   obtuse; 
  aperture 
  small 
  and 
  oval, 
  angled 
  above, 
  rounded 
  f^ 
  

   below, 
  flattened 
  on 
  the 
  parietal 
  margin; 
  lip 
  thick 
  and 
  free 
  ^^ 
  

   from 
  contact 
  with 
  the 
  bodv 
  whorl. 
  Fig. 
  les 
  Am- 
  

  

  •^ 
  nlcola 
  letsoni 
  

  

  Locality. 
  Goat 
  island. 
  ^^ 
  

  

  In 
  his 
  notes 
  Mr 
  Walker 
  says 
  : 
  "Amnicola 
  sheldoni 
  Pils. 
  

   is 
  the 
  only 
  species 
  with 
  which 
  this 
  can 
  be 
  compared. 
  The 
  present 
  

   species 
  is 
  to 
  be 
  distinguished 
  by 
  its 
  flattened, 
  shouldered 
  whorls, 
  

   deeper 
  suture 
  and 
  more 
  acuminate 
  spire. 
  Six 
  mature 
  examples 
  

   were 
  found, 
  which, 
  though 
  differing 
  somewhat 
  in 
  the 
  relative 
  pro- 
  

   portions 
  of 
  length 
  and 
  width, 
  are 
  as 
  a 
  whole 
  quite 
  uniform. 
  In 
  four 
  

   of 
  them 
  the 
  peristome 
  is 
  distinctly 
  separated 
  from 
  the 
  body 
  whorl; 
  

   in 
  one, 
  while 
  continuous, 
  it 
  is 
  so 
  close 
  as 
  to 
  be 
  almost 
  adnate, 
  while 
  

   in 
  the 
  remaining 
  specimens 
  the 
  parietal 
  margin, 
  although 
  somewhat 
  

   broken, 
  seems 
  to 
  have 
  been 
  appressed 
  to 
  the 
  body 
  whorl 
  for 
  a 
  short 
  

   distance. 
  Associated 
  with 
  these 
  specimens 
  were 
  two 
  other 
  ex- 
  

   amples 
  quite 
  similar, 
  but 
  much 
  more 
  cylindrical 
  in 
  the 
  outline, 
  less 
  

   soHd, 
  and 
  with 
  the 
  aperture 
  less 
  angled 
  posteriorly. 
  Neither 
  is 
  

   quite 
  mature, 
  judging 
  from 
  the 
  thinness 
  of 
  the 
  lip. 
  In 
  view 
  of 
  the 
  

   considerable 
  variation 
  in 
  these 
  particulars 
  in 
  other 
  well-known 
  

   species 
  of 
  the 
  genus, 
  such 
  as 
  Amnicola 
  lustrica 
  Pils., 
  and 
  

   of 
  the 
  few 
  specimens 
  now 
  at 
  hand, 
  it 
  is 
  not 
  deemed 
  advisable 
  at 
  

   the 
  present 
  time 
  to 
  do 
  more 
  than 
  call 
  attention 
  to 
  the 
  fact." 
  

  

  What 
  may 
  prove 
  to 
  be 
  other 
  species 
  of 
  Amnicola 
  has 
  been 
  

   found, 
  but 
  too 
  badly 
  worn 
  to 
  justify 
  description. 
  

  

  