﻿OLD 
  AND 
  NEW 
  WORLD 
  MELANIANS 
  — 
  MORRISON 
  361 
  

  

  the 
  Kentucky 
  River, 
  of 
  Oxytrema 
  deshayesiana 
  (Lea) 
  from 
  the 
  Tennes- 
  

   see 
  River, 
  of 
  Oxytrema 
  bvlbosa 
  (Gould) 
  from 
  eastern 
  Oregon, 
  and 
  of 
  

   Oxytrema 
  nodifila 
  (Martens) 
  from 
  the 
  Han 
  River, 
  Korea, 
  have 
  been 
  

   examined 
  by 
  me 
  and 
  sketched 
  to 
  show 
  the 
  egg-laying 
  groove 
  and 
  the 
  

   "ovipositor" 
  pit 
  on 
  the 
  right 
  side 
  of 
  the 
  foot 
  (see 
  pi. 
  11). 
  

  

  Section 
  Strephobasis 
  Lea, 
  1861 
  

  

  The 
  group 
  named 
  Strephobasis 
  by 
  Lea 
  (1861, 
  p. 
  96), 
  with 
  the 
  geno- 
  

   type 
  Oxytrema 
  (Strephobasis) 
  plena 
  Anthony, 
  as 
  stated 
  by 
  Pilsbry 
  

   (1896a, 
  p. 
  496), 
  is 
  only 
  an 
  extreme 
  section 
  of 
  the 
  genus, 
  according 
  to 
  

   shell 
  characters. 
  This 
  small 
  group, 
  which 
  is 
  confined 
  to 
  the 
  larger 
  

   rivers 
  of 
  the 
  upper 
  Tennessee 
  drainage, 
  is 
  exactly 
  parallel 
  to 
  Goniobasis, 
  

   sensu 
  stricto, 
  from 
  the 
  Coosa 
  River 
  di'ainage. 
  The 
  animal 
  characters 
  

   must 
  be 
  examined 
  to 
  determine 
  whether 
  this 
  group 
  is 
  identical 
  to 
  or 
  

   biologically 
  distinct 
  from 
  Oxytrema, 
  sensu 
  stricto, 
  and 
  Goniobasis, 
  

   sensu 
  stricto. 
  

  

  Genus 
  Gyrotoma 
  Shuttleworth, 
  1845 
  

  

  Gyrotoma 
  Shuttleworth 
  (1845, 
  p. 
  88), 
  based 
  on 
  the 
  genotype 
  

   (Gyrotoma 
  ovoideum 
  Shuttleworth 
  =) 
  Gyrotoma 
  excisum 
  (Lea), 
  is 
  con- 
  

   fined 
  to 
  the 
  Coosa 
  River 
  drainage. 
  As 
  Goodrich 
  (1924, 
  p. 
  6) 
  has 
  

   hinted, 
  the 
  group 
  named 
  Goniobasis 
  by 
  Lea 
  in 
  1862 
  (genotype 
  by 
  

   subsequent 
  designation 
  by 
  Hannibal 
  1912: 
  G. 
  osculata 
  Lea) 
  may 
  

   eventually 
  prove 
  to 
  be 
  most 
  closely 
  related 
  to 
  Gyrotoma. 
  It 
  is 
  possible 
  

   that 
  Goniobasis, 
  sensu 
  stricto, 
  may 
  be 
  a 
  subgenus 
  of 
  Gyrotoma 
  different 
  

   only 
  by 
  lack 
  of 
  or 
  development 
  of 
  the 
  fissure 
  in 
  the 
  lip. 
  Study 
  of 
  the 
  

   animal 
  characters 
  (as 
  yet 
  unknown) 
  of 
  the 
  genotype 
  must 
  prove 
  the 
  

   true 
  biological 
  position 
  of 
  Goniobasis. 
  

  

  Genus 
  Mudalia 
  Haldeman, 
  1840 
  

  

  Mudalia 
  of 
  Haldeman, 
  whose 
  genotype 
  is 
  Mudalia 
  carinata 
  (Bru- 
  

   guiere) 
  from 
  the 
  Atlantic 
  coastal 
  region, 
  includes 
  trilineata 
  (Say) 
  of 
  the 
  

   Ohio 
  River 
  and 
  the 
  more 
  widespread 
  "Goniobasis" 
  livescens 
  (Menl^e) 
  

   from 
  the 
  upper 
  St. 
  Lawrence 
  River 
  and 
  upper 
  Mississippi 
  River 
  areas. 
  

   The 
  single 
  carina 
  typical 
  of 
  adolescent 
  shells 
  and 
  the 
  egg-laying 
  habits 
  

   are 
  identical 
  in 
  carinate 
  (Winsor, 
  1933) 
  and 
  in 
  livescens 
  (Jewell, 
  1931). 
  

   Figures 
  10 
  and 
  14 
  of 
  Goodrich 
  (1945, 
  pi. 
  1) 
  show 
  how 
  closely 
  the 
  shape 
  

   of 
  adult 
  shells 
  of 
  livescens 
  may 
  vary 
  toward 
  the 
  usual 
  shape 
  of 
  adult 
  

   shells 
  of 
  carinata. 
  The 
  eggs 
  of 
  Mudalia 
  are 
  laid 
  singly; 
  that 
  is, 
  there 
  is 
  

   only 
  one 
  egg 
  capsule 
  in 
  each 
  egg 
  mass. 
  

  

  Genus 
  Leptoxis 
  Rafinesque, 
  1819 
  

  

  Leptoxis 
  of 
  Rafinesque 
  is 
  the 
  earliest 
  name 
  available 
  for 
  the 
  Ameri- 
  

   can 
  species 
  related 
  to 
  the 
  genotype 
  L. 
  praerosa 
  (Say), 
  and 
  must 
  be 
  so 
  

   used. 
  Pilsbry 
  (1917, 
  p. 
  113) 
  has 
  stated 
  the 
  case 
  for 
  priority 
  of 
  Lep- 
  

  

  