﻿368 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM 
  vol. 
  io3 
  

  

  wholly 
  North 
  American. 
  The 
  generic 
  name 
  Hua, 
  proposed 
  by 
  S. 
  F. 
  

   Chen 
  (1943, 
  p. 
  21) 
  for 
  the 
  group 
  of 
  "Melania" 
  telonaria 
  Heude 
  1888, 
  

   is 
  a 
  synonym 
  of 
  Oxytrema 
  Eafinesque 
  1819. 
  As 
  is 
  the 
  case 
  in 
  both 
  

   the 
  Appalachian 
  and 
  Rocky 
  Mountain 
  regions 
  of 
  North 
  America, 
  

   the 
  genus 
  Oxytrema 
  is 
  represented 
  in 
  eastern 
  Asia 
  (Korea, 
  China, 
  

   and 
  Thailand) 
  by 
  some 
  species 
  that 
  are 
  generally 
  smooth 
  (Hua) 
  

   and 
  some 
  with 
  strongly 
  nodose 
  or 
  reticulate 
  sculpture. 
  Heude 
  

   figured 
  the 
  female 
  pleurocerine 
  external 
  anatomy 
  of 
  Oxytrema 
  in 
  

   1890 
  in 
  his 
  excellent 
  work 
  on 
  the 
  Chinese 
  fresh-water 
  mollusks. 
  

   Unfortunately, 
  he 
  misunderstood 
  the 
  structures 
  of 
  the 
  females 
  of 
  

   such 
  species 
  as 
  "Melania" 
  jacquetiana 
  Heude 
  and 
  called 
  them 
  male 
  

   individuals. 
  At 
  present, 
  Heude's 
  mistake 
  is 
  easy 
  to 
  explain. 
  The 
  

   (female) 
  egg-laying 
  apparatus 
  of 
  these 
  species 
  (Heude 
  1890, 
  pi. 
  43, 
  

   fig. 
  5) 
  is 
  superficially 
  identical 
  in 
  appearance 
  to 
  the 
  (male) 
  intromittent 
  

   organ 
  of 
  certain 
  operculate 
  land 
  snails 
  of 
  the 
  subfamily 
  Cyclophorinae 
  

   (family 
  Cyclophoridae) 
  (see 
  Heude 
  1890, 
  pi. 
  42, 
  fig. 
  12c), 
  as 
  a 
  com- 
  

   parison 
  of 
  Heude's 
  own 
  figures 
  will 
  demonstrate. 
  It 
  is 
  this 
  extreme 
  

   similarity 
  in 
  appearance 
  that 
  led 
  Heude 
  to 
  an 
  understandable 
  mis- 
  

   interpretation 
  and 
  has 
  effectively 
  hidden 
  the 
  complete 
  understanding 
  

   of 
  his 
  critical 
  discoveries 
  for 
  many 
  years. 
  

  

  The 
  present 
  studies 
  have 
  corroborated 
  those 
  of 
  Heude. 
  The 
  

   animals 
  of 
  Oxytrema 
  telonaria 
  (Heude) 
  1888 
  are 
  dioecious; 
  the 
  sexes 
  

   may 
  be 
  distinguished 
  by 
  the 
  presence 
  or 
  absence 
  of 
  the 
  female 
  genital 
  

   groove 
  on 
  the 
  right 
  side 
  of 
  the 
  foot. 
  There 
  is 
  a 
  glandular, 
  egg-laying 
  

   pit 
  at 
  the 
  terminal 
  end 
  of 
  the 
  groove 
  a 
  little 
  above 
  the 
  right 
  edge 
  of 
  

   the 
  foot. 
  The 
  epithelium 
  lining 
  this 
  groove 
  is 
  markedly 
  different 
  

   from 
  that 
  of 
  the 
  adjacent 
  area 
  and 
  is 
  easily 
  distinguished 
  in 
  preserved 
  

   material. 
  The 
  posterior 
  edge 
  of 
  the 
  groove 
  is 
  projected 
  into 
  the 
  pit 
  

   as 
  a 
  sort 
  of 
  papilla 
  at 
  its 
  termination. 
  The 
  oviduct 
  is 
  not 
  enlarged 
  

   into 
  a 
  uterus; 
  there 
  are 
  no 
  embryos 
  in 
  the 
  body 
  behind 
  the 
  head. 
  

   Animals 
  of 
  the 
  followmg 
  Asiatic 
  species 
  have 
  been 
  personally 
  examined 
  

   and 
  found 
  to 
  exhibit 
  the 
  same 
  pleurocerine 
  reproductive 
  anatomy 
  

   with 
  but 
  little 
  difference 
  in 
  minor 
  details: 
  0. 
  nodijila 
  (Martens) 
  1886, 
  

   Han 
  River, 
  Korea 
  (see 
  pi. 
  11, 
  fig. 
  3); 
  0. 
  toucheana 
  (Heude) 
  1888, 
  

   Min 
  River, 
  Fukien, 
  China; 
  0. 
  jacquetiana 
  (Heude) 
  1890, 
  Shaohsing, 
  

   Chekiang, 
  China; 
  0. 
  peregrinorum 
  (Heude) 
  1890, 
  Fukien, 
  China; 
  

   0. 
  moutoniana 
  (Heude) 
  1890, 
  Sa-Hsien, 
  Fukien, 
  China; 
  0. 
  joretiana 
  

   (Heude) 
  1890, 
  Chekiang, 
  China; 
  and 
  0. 
  bailleti 
  (Bavay 
  and 
  Dautzen- 
  

   berg) 
  1910, 
  Szechwan, 
  China. 
  How 
  many 
  of 
  the 
  other 
  Asiatic 
  species 
  

   listed 
  by 
  S. 
  F. 
  Chen 
  in 
  these 
  groups 
  will 
  prove 
  to 
  belong 
  to 
  Oxytrema 
  

   can 
  be 
  determined 
  only 
  when 
  their 
  reproductive 
  anatomy 
  is 
  examined. 
  

   The 
  presence 
  of 
  Oxytrema 
  species 
  in 
  the 
  recent 
  fauna 
  on 
  both 
  sides 
  of 
  

   the 
  North 
  Pacific 
  Ocean 
  demonstrates 
  a 
  geographic 
  distribution 
  similar 
  

   to 
  that 
  of 
  the 
  genera 
  Viviparus 
  and 
  Anodonta, 
  sensu 
  stricto. 
  It 
  is 
  

  

  