﻿OLD 
  AND 
  NEW 
  WORLD 
  MELANIANS 
  — 
  MORRISON 
  371 
  

  

  Potadominae 
  Pilsbry 
  and 
  Bequaert 
  and 
  the 
  Paludominae 
  are 
  included 
  

   synonyms. 
  In 
  addition 
  to 
  the 
  species 
  called 
  Potadoma 
  by 
  Pilsbry 
  

   and 
  Bequaert, 
  some 
  of 
  the 
  species 
  they 
  called 
  ''Melanoides" 
  also 
  belong 
  

   to 
  Potadoma 
  of 
  Swainson. 
  "Melanoides" 
  species 
  such 
  as 
  ignohilis 
  

   (Thiele) 
  (Pilsbry 
  and 
  Bequaert, 
  1927, 
  p. 
  278, 
  pi. 
  26, 
  figs. 
  1, 
  2) 
  are 
  

   smooth; 
  others 
  such 
  as 
  medjeorum 
  Pilsbry 
  and 
  Bequaert 
  (1927, 
  p. 
  283, 
  

   fig. 
  47) 
  and 
  tornata 
  (Martens) 
  (Pilsbry 
  and 
  Bequaert, 
  1927, 
  p. 
  283, 
  fig. 
  

   48) 
  possess 
  strong 
  spiral 
  sculpture. 
  Still 
  others, 
  such 
  as 
  wagenia 
  Pilsbry 
  

   and 
  Bequaert 
  (1927, 
  p. 
  262, 
  pi. 
  22, 
  figs. 
  14-16), 
  crawshayi 
  (E. 
  A. 
  Smith) 
  

   and 
  mweruensis 
  (E. 
  A. 
  Smith) 
  (Pilsbry 
  and 
  Bequaert, 
  1927, 
  pp. 
  264- 
  

   265, 
  pi. 
  22, 
  figs. 
  19-22) 
  show 
  strong 
  plicate 
  to 
  cancellate 
  shell 
  sculpture. 
  

   The 
  total 
  picture 
  of 
  sculpture 
  in 
  this 
  genus 
  seems 
  exactly 
  parallel 
  to 
  

   that 
  seen 
  in 
  Appalachia, 
  western 
  America, 
  and 
  eastern 
  Asia 
  in 
  the 
  

   genus 
  Oxytrema. 
  

  

  Genus 
  Limnotrochus 
  E. 
  A. 
  Smith, 
  1880 
  

  

  1880. 
  Limnotrochus 
  E. 
  A. 
  Smith, 
  1880b, 
  p. 
  425. 
  (Genotype, 
  Limnotrochus 
  

  

  thomsoni, 
  E. 
  A. 
  Smith, 
  1880.) 
  

  

  Genus 
  Paramelania 
  E. 
  A. 
  Smith, 
  1881 
  

  

  1881. 
  Paramelania 
  E. 
  A. 
  Smith, 
  1881b, 
  p. 
  559. 
  (Genotype, 
  Paramelania 
  

  

  damoni 
  E. 
  A. 
  Smith, 
  1881, 
  by 
  subsequent 
  designation 
  by 
  Pilsbry 
  and 
  

   Bequaert, 
  1927, 
  p. 
  320.) 
  

  

  Genus 
  Spekia 
  Bourguignat, 
  1879 
  

  

  1879. 
  Spekia 
  Bourguignat, 
  1879, 
  p. 
  27. 
  (Genotype, 
  Spekia 
  zonatus 
  (Woodward), 
  

   1859, 
  by 
  monotypy.) 
  

  

  Pilsbry 
  and 
  Bequaert 
  have 
  said 
  that, 
  as 
  far 
  as 
  known, 
  the 
  three 
  

   above-named 
  genera 
  are 
  oviparous. 
  If 
  complete 
  study 
  of 
  the 
  animals 
  

   confirm-s 
  this 
  and 
  reveals 
  the 
  characteristic 
  egg-la3ang 
  pit 
  in 
  the 
  side 
  

   of 
  the 
  foot, 
  these 
  Lake 
  Tanganyika 
  forms 
  are 
  also 
  Pleurocerinae. 
  

   Moore 
  (1899a, 
  p. 
  171) 
  found 
  neither 
  an 
  external 
  groove 
  nor 
  a 
  brood 
  

   pouch 
  of 
  any 
  type 
  in 
  the 
  females 
  of 
  Spekia 
  zonafa 
  (Woodward) 
  

   examxined 
  by 
  him. 
  This 
  condition 
  seems 
  identical 
  in 
  appearance 
  to 
  

   that 
  of 
  those 
  North 
  American 
  members 
  of 
  the 
  pleurocerine 
  genus 
  

   Oxytrema, 
  in 
  which 
  the 
  female 
  egg-laying 
  groove 
  is 
  not 
  demarcated 
  

   structurally 
  and 
  can 
  only 
  be 
  seen 
  functionally 
  as 
  a 
  linear 
  depression 
  

   in 
  the 
  skin 
  during 
  the 
  breeding 
  season. 
  

  

  Subfamily 
  lavigeriinae 
  Thiele, 
  1929 
  

  

  The 
  statement 
  of 
  Pilsbry 
  and 
  Bequaert 
  (1927, 
  p. 
  300) 
  in 
  regard 
  to 
  

   the 
  ovoviviparity 
  of 
  the 
  mixture 
  of 
  species 
  they 
  called 
  "Melanoides" 
  is 
  

   in 
  need 
  of 
  clarification. 
  They 
  left 
  the 
  problem 
  unsolved 
  when 
  they 
  

   said: 
  "Typhohia, 
  Bathanalia, 
  and 
  Lavigeria 
  are 
  viviparous, 
  having 
  the 
  

  

  