﻿372 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM 
  vol. 
  los 
  

  

  last 
  part 
  of 
  the 
  oviduct 
  enlarged 
  to 
  form 
  a 
  brood 
  pouch 
  in 
  the 
  mantle, 
  

   as 
  in 
  Melanoides 
  and 
  Viviparus." 
  The 
  fact 
  is 
  that 
  Melanoides 
  does 
  

   not 
  have 
  a 
  uterine 
  brood 
  pouch 
  as 
  in 
  the 
  family 
  Viviparidae. 
  True 
  

   Melanoides 
  species 
  have 
  the 
  subhaemocoelic 
  brood 
  pouch 
  in 
  the 
  back 
  

   of 
  the 
  neck, 
  with 
  the 
  brood 
  pouch 
  pore 
  on 
  the 
  right, 
  as 
  in 
  all 
  other 
  

   members 
  of 
  the 
  Thiaridae. 
  

  

  If 
  Pilsbry 
  and 
  Bequaert 
  actually 
  saw 
  uterine 
  brood 
  pouches 
  in 
  the 
  

   animals 
  of 
  any 
  African 
  species 
  of 
  "Melanoides," 
  they 
  probably 
  were 
  

   dealing 
  with 
  members 
  of 
  the 
  subfamily 
  Lavigeriinae, 
  of 
  an 
  unnamed 
  

   genus. 
  In 
  this 
  connection, 
  the 
  possibility 
  should 
  be 
  stated 
  frankly 
  

   that 
  the 
  subfamilies 
  Lavigeriinae 
  and 
  Tiphobiinae 
  may 
  in 
  the 
  future 
  

   prove 
  to 
  be 
  biologically 
  confluent. 
  Much 
  more 
  study 
  of 
  the 
  animals 
  of 
  

   African 
  fresh-water 
  species 
  both 
  in 
  and 
  out 
  of 
  Lake 
  Tanganyika 
  is 
  

   needed 
  to 
  prove 
  or 
  disprove 
  this 
  possibility. 
  As 
  defined 
  above, 
  the 
  

   subfamily 
  Lavigeriinae 
  includes 
  those 
  genera 
  of 
  pleurocerid 
  snails 
  in 
  

   which 
  the 
  males 
  have 
  no 
  intromittent 
  organ 
  and 
  the 
  females 
  possess 
  

   uterine 
  brood 
  pouches. 
  

  

  Genus 
  Lavigeria 
  Bourguignat, 
  1888 
  

  

  The 
  genus 
  Lavigeria 
  Bourguignat 
  (1888, 
  p. 
  33) 
  is 
  another 
  of 
  the 
  

   peculiar 
  pleurocerid 
  forms 
  found 
  in 
  Lake 
  Tanganyika. 
  In 
  addition 
  to 
  

   the 
  shell 
  characters, 
  this 
  genus 
  differs 
  from 
  others 
  by 
  its 
  operculum, 
  

   which 
  is 
  modified 
  by 
  partial 
  uncoiling 
  to 
  a 
  subspiral 
  form. 
  Moore 
  

   1899b, 
  p. 
  192, 
  pi. 
  20, 
  fig. 
  6) 
  has 
  furnished 
  anatomical 
  studies 
  of 
  the 
  

   species 
  Lavigeria 
  coronata 
  Bourguignat. 
  He 
  called 
  the 
  animal 
  "Nas- 
  

   sopsis 
  nassa 
  Woodward," 
  while 
  Pilsbry 
  and 
  Bequaert 
  have 
  referred 
  

   this 
  anatomical 
  study 
  to 
  the 
  genotype 
  which 
  they 
  designated, 
  namely: 
  

   Lavigeria 
  grandis 
  (E. 
  A. 
  Smith) 
  1881. 
  Moore's 
  figure 
  of 
  the 
  shell 
  

   proves 
  he 
  studied 
  the 
  species 
  coronata. 
  He 
  found 
  that 
  this 
  genus 
  

   possesses 
  a 
  uterine 
  brood 
  pouch 
  similar 
  to 
  that 
  of 
  Viviparus 
  and 
  of 
  

   the 
  Tiphobiinae. 
  According 
  to 
  him, 
  the 
  males 
  do 
  not 
  possess 
  any 
  

   secondarily 
  developed 
  intromittent 
  organ 
  such 
  as 
  is 
  found 
  in 
  the 
  

   mantle 
  edge 
  of 
  the 
  males 
  of 
  Tiphohia. 
  

  

  Genus 
  Bourguignatia 
  Giraud, 
  1885 
  

  

  1885. 
  Bourguignatia 
  Giraud, 
  1885, 
  p. 
  193, 
  pi. 
  7, 
  figs. 
  5-7. 
  (Genotype, 
  Bourguigna- 
  

   tia 
  imperialis 
  Giraud, 
  1885, 
  by 
  monotypy.) 
  

  

  Genus 
  Edgaria 
  Bourguignat, 
  1888 
  

  

  1888. 
  Edgaria 
  Bourguignat, 
  1888, 
  p. 
  33. 
  (Genotype, 
  Edgaria 
  paucicostata 
  (E. 
  A. 
  

   Smith), 
  1881, 
  by 
  subsequent 
  designation 
  by 
  Pilsbry 
  and 
  Bequaert, 
  1927, 
  

   p. 
  328.) 
  

  

  The 
  shells 
  of 
  the 
  Bourguignatia, 
  Lavigeria, 
  Edgaria, 
  and 
  Paramelania 
  

   complex 
  of 
  Lake 
  Tanganyika 
  are 
  almost 
  identical 
  in 
  general 
  characters 
  ; 
  

   however, 
  there 
  are 
  two 
  distinct 
  types 
  of 
  opercula 
  known 
  in 
  the 
  group. 
  

  

  