﻿OLD 
  AND 
  NEW 
  WORLD 
  MELANIANS 
  — 
  MORRISON 
  359 
  

  

  According 
  to 
  studies 
  by 
  Ankel 
  (1928), 
  Fagotia 
  esperi 
  (Ferussac) 
  

   has 
  the 
  same 
  reproductive 
  anatomy 
  of 
  the 
  female 
  as 
  does 
  Melanopsis. 
  

   The 
  few 
  large 
  eggs 
  (1 
  mm. 
  in 
  size) 
  are 
  laid 
  singly 
  in 
  an 
  irregular 
  capsule. 
  

  

  Melanopsis 
  dufourii 
  (Ferussac) 
  from 
  Elche, 
  Alicante 
  Province, 
  

   Spain, 
  has 
  been 
  examined 
  by 
  me. 
  Unlike 
  the 
  animals 
  of 
  the 
  North 
  

   American 
  Pleuroceridae, 
  in 
  this 
  species 
  at 
  least, 
  the 
  smooth 
  mantle 
  

   edge 
  is 
  continuous 
  beneath 
  the 
  back 
  of 
  the 
  foot, 
  forming 
  a 
  circle 
  around 
  

   the 
  aperture. 
  In 
  the 
  female 
  the 
  end 
  of 
  the 
  oviduct 
  is 
  quite 
  far 
  behind 
  

   the 
  mantle 
  edge 
  and 
  simple, 
  as 
  is 
  typical 
  for 
  the 
  group. 
  The 
  egg- 
  

   laying 
  groove 
  is 
  not 
  long, 
  and 
  does 
  not 
  even 
  reach 
  the 
  mantle 
  edge. 
  

   The 
  pit 
  is 
  enormously 
  developed 
  and 
  has 
  a 
  large, 
  whitish, 
  tongue- 
  

   shaped, 
  basally-attached 
  "ovipositor," 
  with 
  a 
  gi'oove 
  on 
  its 
  posterior 
  

   dorsal 
  face, 
  toward 
  the 
  rest 
  of 
  the 
  pit. 
  According 
  to 
  Ankel 
  (1928), 
  

   a 
  few 
  proportionately 
  large 
  eggs 
  are 
  laid 
  by 
  Melanopsis. 
  

  

  Family 
  Pleuroceridae 
  (in 
  the 
  Americas) 
  

   Subfamily 
  pleurocerinae 
  

  

  All 
  known 
  American 
  members 
  of 
  Pleuroceridae 
  are 
  oviparous, 
  

   including 
  those 
  from 
  North, 
  Central, 
  and 
  South 
  America 
  and 
  the 
  

   West 
  Indies. 
  In 
  other 
  words, 
  every 
  American 
  genus 
  and 
  species 
  for 
  

   which 
  the 
  characters 
  of 
  reproduction 
  are 
  known 
  is 
  egg-laying, 
  with 
  an 
  

   egg-laying 
  sinus 
  or 
  pit 
  in 
  the 
  right 
  side 
  of 
  the 
  foot 
  of 
  the 
  females. 
  The 
  

   presence 
  of 
  this 
  pit 
  is 
  the 
  single 
  morphological 
  character 
  that 
  proves 
  

   them 
  to 
  belong 
  to 
  the 
  typical 
  subfamily. 
  There 
  is 
  every 
  indication 
  

   that 
  all 
  the 
  American 
  genera 
  and 
  species 
  of 
  Pleuroceridae 
  belong 
  here, 
  

   although 
  some 
  of 
  the 
  North 
  American 
  genera 
  are 
  still 
  unrecorded 
  as 
  to 
  

   critical 
  animal 
  characters. 
  

  

  Subfamily 
  pleurocerinae 
  (in 
  North 
  America) 
  

   Genus 
  Oxytrema 
  Rafinesque, 
  1819 
  

  

  Oxytrema 
  Rafinesque 
  is 
  the 
  earliest 
  and 
  correct 
  name 
  for 
  one 
  of 
  the 
  

   most 
  widespread 
  "Melanian" 
  genera 
  in 
  the 
  world. 
  This 
  genus 
  in- 
  

   cludes 
  numerous 
  North 
  American 
  species 
  whose 
  ranges 
  extend 
  from 
  

   the 
  Atlantic 
  to 
  the 
  Pacific 
  coasts 
  and 
  from 
  southern 
  Canada 
  to 
  Florida 
  

   and 
  Texas. 
  It 
  also 
  includes 
  North 
  American 
  fossils, 
  as 
  well 
  as 
  a 
  num- 
  

   ber 
  of 
  Recent 
  species 
  from 
  southeast 
  Asia 
  (Korea, 
  China, 
  and 
  Thailand). 
  

   All 
  the 
  species 
  called 
  "Pleurocera" 
  by 
  Bryant 
  Walker, 
  and 
  other 
  

   authors 
  who 
  followed 
  him 
  blindly, 
  and 
  all 
  the 
  species 
  called 
  "Goni- 
  

   obasis" 
  (with 
  very 
  few 
  exceptions) 
  belong 
  to 
  this 
  genus. 
  Their 
  eggs 
  

   are 
  laid 
  in 
  a 
  single 
  row 
  in 
  a 
  close, 
  irregularly 
  spiral 
  group, 
  in 
  apparent 
  

   flat 
  clusters 
  of 
  3 
  to 
  10 
  egg 
  capsules 
  in 
  each 
  small 
  egg 
  mass, 
  the 
  whole 
  

   covered 
  with 
  sand 
  grains 
  as 
  recorded 
  by 
  Van 
  Cleave 
  (1932), 
  Winsor 
  

   (1933), 
  and 
  Woodward 
  (1934). 
  

  

  