﻿OLD 
  AND 
  NEW 
  WORLD 
  MELANL/USTS 
  — 
  MORRISON 
  373 
  

  

  Our 
  present 
  lack 
  of 
  anatomical 
  knowledge 
  of 
  all 
  but 
  Lavigeria 
  makes 
  

   it 
  impossible 
  to 
  say 
  whether 
  two 
  or 
  more 
  subfamilies 
  are 
  represented 
  

   in 
  this 
  complex 
  of 
  shells 
  inhabiting 
  the 
  rocky 
  shorelines 
  of 
  Lake 
  

   Tanganyika. 
  

  

  Genus 
  Bythoceras 
  Moore, 
  1898 
  

  

  1898. 
  Bythoceras 
  Moore, 
  1898c, 
  p. 
  452. 
  (Genotype, 
  Bythoceras 
  iridescens 
  Moore, 
  

   1898, 
  by 
  monotypy.) 
  

  

  These 
  shells 
  from 
  deeper 
  waters 
  of 
  Lake 
  Tanganyika 
  are 
  also 
  very 
  

   similar 
  to 
  those 
  of 
  the 
  Lavigeria 
  complex; 
  their 
  opercula 
  differ 
  from 
  

   those 
  of 
  Lavigeria 
  in 
  being 
  secondarily 
  concentric 
  around 
  a 
  paucispiral 
  

   nucleus. 
  The 
  general 
  statement 
  by 
  Moore 
  (1898d) 
  that 
  Bythoceras 
  

   is 
  much 
  more 
  like 
  Tanganyicia 
  in 
  anatomy 
  than 
  (" 
  Nassopsis"==) 
  

   Lavigeria 
  is 
  in 
  need 
  of 
  corroboration 
  or 
  clarification. 
  Neither 
  

   is 
  it 
  clear 
  from 
  Moore's 
  subsequent 
  statements 
  and 
  figures 
  (1899b) 
  

   whether 
  Bythoceras 
  is 
  ovoviviparous 
  or 
  not. 
  

  

  The 
  final 
  allocation 
  of 
  these 
  names 
  and 
  also 
  of 
  Paramelania 
  and 
  the 
  

   subfamily 
  name 
  Paramelaniinae 
  must 
  await 
  the 
  complete 
  recording 
  

   of 
  shell, 
  opercular, 
  and 
  reproductive 
  characters 
  of 
  all 
  members 
  of 
  the 
  

   Lavigeria 
  complex 
  of 
  Lake 
  Tanganyika. 
  If 
  the 
  reproductive 
  anatomy 
  

   proves 
  identical, 
  Paramelaniinae 
  (Moore, 
  1898b, 
  p. 
  315) 
  will 
  super- 
  

   sede 
  the 
  name 
  Lavigeriinae 
  (Thiele, 
  1929, 
  pp. 
  79, 
  83) 
  used 
  at 
  this 
  time. 
  

  

  Subfamily 
  tiphobiinae 
  Moore, 
  1898 
  

  

  These 
  are 
  pleurocerid 
  snails 
  modified 
  in 
  the 
  males 
  by 
  the 
  develop- 
  

   ment 
  of 
  a 
  secondary, 
  eversible 
  "penis" 
  or 
  vergic 
  structure 
  in 
  the 
  

   mantle 
  edge 
  near 
  the 
  end 
  of 
  the 
  vas 
  deferens. 
  As 
  far 
  as 
  known, 
  these 
  

   are 
  the 
  only 
  "Melanian" 
  snails 
  of 
  any 
  kind 
  that 
  possess 
  any 
  intro- 
  

   mittent 
  structures 
  whatsoever. 
  The 
  females 
  are 
  ovoviviparous, 
  with 
  

   the 
  terminal 
  portion 
  of 
  the 
  oviduct 
  modified 
  into 
  a 
  uterine 
  brood 
  

   pouch 
  for 
  the 
  young. 
  At 
  present, 
  our 
  knowledge 
  — 
  or 
  lack 
  of 
  

   knowledge 
  — 
  indicates 
  that 
  the 
  Tiphobiinae 
  are 
  solely 
  African 
  in 
  

   geographic 
  distribution, 
  parallel 
  to 
  but 
  not 
  identical 
  with 
  the 
  Asiatic 
  

   and 
  African 
  subfamily 
  Lavigeriinae. 
  

  

  Genus 
  Tiphohia 
  E. 
  A. 
  Smith, 
  1880 
  

  

  The 
  genotype 
  of 
  Tiphobia 
  E. 
  A. 
  Smith 
  (1880a, 
  p. 
  348, 
  pi. 
  31, 
  fig. 
  6), 
  

   T. 
  horei 
  E. 
  A. 
  Smith, 
  1880, 
  possesses 
  the 
  reproductive 
  characters 
  of 
  

   the 
  subfamily, 
  as 
  defined 
  above, 
  according 
  to 
  the 
  studies 
  of 
  Moore 
  

   (1898a). 
  The 
  statement 
  of 
  Pilsbry 
  and 
  Bequaert 
  that 
  the 
  characters 
  

   of 
  the 
  Tiphobiidae 
  do 
  not 
  distinguish 
  them 
  from 
  the 
  Melaniidae 
  is 
  

   based 
  on 
  their 
  misunderstanding 
  of 
  the 
  true 
  nature 
  of 
  the 
  brood 
  

   pouch 
  of 
  the 
  Thiaridae 
  ("Melaniidae"). 
  Tiphohia 
  is 
  one 
  of 
  the 
  

   endemic 
  genera 
  of 
  Lake 
  Tanganyika, 
  with 
  a 
  spinose 
  shell 
  and 
  a 
  

  

  