﻿NIAGARA 
  FALLS 
  AND 
  VICINITY 
  245 
  

  

  Physa 
  heterostropha 
  Say 
  1821 
  (Fig. 
  174). 
  Limnaea 
  he- 
  

   terostropha 
  Say 
  (1817-19. 
  Nich. 
  cue. 
  Am. 
  cd. 
  pi. 
  i, 
  fig. 
  6). 
  

   Physa 
  heterostropha 
  Say 
  (1821. 
  Acad. 
  nat. 
  

   sci. 
  Phil. 
  Jour. 
  2:172) 
  

  

  Shell 
  oval 
  and 
  smooth, 
  sinistral; 
  whorls 
  four, 
  the 
  first 
  

   large, 
  the 
  others 
  very 
  small 
  and 
  terminating 
  in 
  an 
  acute 
  

   apex; 
  aperture 
  large 
  and 
  oval, 
  about 
  half 
  the 
  length 
  of 
  the 
  

   shell; 
  outer 
  lip 
  a 
  Httle 
  thickened, 
  inner 
  lip 
  folded 
  back 
  on 
  Fis^mphysa 
  

   the 
  columella, 
  forming 
  a 
  slight 
  callus. 
  heterostropha. 
  

  

  Localities. 
  Goat 
  island, 
  Whirlpool 
  and 
  Foster's 
  flats. 
  

  

  Genus 
  PLANORBis 
  Guettard. 
  1756 
  

  

  The 
  animal 
  of 
  P 
  1 
  a 
  n 
  o 
  r 
  b 
  i 
  s 
  has 
  a 
  broad 
  foot, 
  and 
  long 
  slender 
  

   tentacles. 
  The 
  shell 
  is 
  dextral 
  and 
  discoidal; 
  the 
  spire 
  depressed, 
  

   and 
  the 
  whorls 
  numerous 
  and 
  visible 
  on 
  both 
  sides; 
  the 
  aperture 
  is 
  

   transversely 
  oval, 
  with 
  a 
  thin 
  lip. 
  

  

  Planorbis 
  bicarinatus 
  Say 
  1817 
  (Fig. 
  175). 
  Planorbis 
  

   bicarinatus 
  Say 
  (181 
  7-19. 
  Nich. 
  cue. 
  Am. 
  cd. 
  pi. 
  i, 
  fig. 
  4) 
  

  

  Shell 
  sinistral; 
  sharply 
  carinated 
  on 
  both 
  sides; 
  

   all 
  the 
  whorls 
  may 
  be 
  seen 
  from 
  either 
  side; 
  aper- 
  

   ture 
  vaulted 
  above, 
  angulated 
  below; 
  surface 
  

   wrinkled 
  with 
  growth 
  lines 
  at 
  regular 
  distances 
  and 
  

   surrounded 
  by 
  fine 
  revolving 
  striae. 
  

  

  earinatus.'^x2°^ 
  ^ 
  ' 
  Locality. 
  Fouud 
  only 
  in 
  the 
  gravel 
  on 
  Goat 
  

   island. 
  

  

  Planorbis 
  parvus 
  Say 
  1817 
  (Fig. 
  176). 
  P. 
  parvus 
  Say 
  

  

  (181 
  7- 
  19. 
  Nich. 
  cnc. 
  Am. 
  cd. 
  pi. 
  i, 
  fig. 
  5). 
  P. 
  parvus 
  

  

  Say 
  (1865. 
  Smith. 
  Misc. 
  coll. 
  no. 
  144, 
  p. 
  133) 
  

  

  Shell 
  small, 
  with 
  four 
  whorls 
  crossed 
  by 
  wrinkles 
  or 
  

   growth 
  lines; 
  concave 
  above 
  and 
  below; 
  body 
  whorl 
  Fig. 
  ne 
  pian- 
  

   slightly 
  swollen; 
  mouth 
  oblique, 
  with 
  the 
  lip 
  simple. 
  orbis 
  parvus. 
  x2 
  

  

  Locality. 
  Goat 
  island 
  and 
  Foster's 
  flats. 
  

  

  Class 
  PELECYPODA 
  Goldfuss 
  

   Genus 
  sphaericm 
  ScopoH. 
  1777 
  

  

  General 
  shape 
  of 
  the 
  animal 
  oval, 
  margins 
  plain, 
  united 
  behind 
  

   and 
  ending 
  in 
  two 
  short 
  siphons, 
  which 
  are 
  joined 
  at 
  their 
  base; 
  

   mouth 
  oval 
  and 
  small; 
  gills 
  broad 
  and 
  unequal, 
  the 
  inner 
  ones 
  

   largest; 
  the 
  foot 
  tongue-shaped, 
  triangular, 
  flattened 
  and 
  very 
  ex- 
  

   tensible. 
  Shell 
  thin, 
  oval, 
  often 
  inflated, 
  with 
  prominent 
  beaks; 
  

  

  