﻿akt. 
  4 
  SCULPTURE 
  OF 
  MUSSEL 
  SHELLS 
  MARSHALL 
  13 
  

  

  6. 
  The. 
  sinulus 
  • 
  and 
  tooth 
  of 
  some 
  of 
  the 
  shells 
  of 
  the 
  genus 
  

   Pseudodon 
  of 
  eastern 
  Asia 
  and 
  near-by 
  islands 
  present 
  a 
  problem. 
  

   It 
  is 
  believed 
  that 
  they 
  do 
  not 
  indicate 
  any 
  close 
  relationship 
  of 
  

   this 
  genus 
  to 
  the 
  Mutelidae. 
  

  

  7. 
  The 
  triangular 
  sinulus, 
  the 
  absence 
  of 
  teeth, 
  and 
  the 
  South 
  

   American 
  habitat 
  of 
  the 
  genera 
  Mulleria 
  and 
  Bartlettia 
  of 
  the 
  

   family 
  Aetheriidae 
  seem 
  to 
  indicate 
  some 
  close 
  relation 
  of 
  this 
  

   family 
  with 
  the 
  Mutelidae, 
  The 
  periostracum 
  of 
  Mulleria 
  and 
  

   Bartlettia 
  shows 
  no 
  sign 
  of 
  radiating 
  threads. 
  Further 
  study 
  of 
  

   this 
  family 
  with 
  young 
  specimens 
  is 
  desirable. 
  

  

  8. 
  The 
  number 
  of 
  striae 
  on 
  the 
  shells 
  in 
  which 
  a 
  count 
  has 
  been 
  

   made 
  was: 
  Pet 
  . 
  millimeter 
  

  

  Spatha 
  wahlbergi 
  Krauss 
  300 
  

  

  Pleiodon 
  ovatus 
  Swainson 
  105 
  

  

  Monocondylaea 
  franciscana 
  Moricand 
  85 
  

  

  Monocondylaca 
  felipponei 
  Marshall 
  110 
  

  

  Fossula 
  fossiculifera 
  Lea 
  105 
  

  

  Anondontites 
  crispatus 
  Bruguiere 
  80 
  

  

  Anondontites 
  tenebricosus 
  Lea 
  130 
  

  

  Anodontitcs 
  patagonicus 
  Lamarck 
  90 
  

  

  Anodontitcs 
  inaequivalvis 
  100 
  

  

  " 
  Solenma 
  " 
  falcata 
  Higgins 
  90 
  

  

  Diplodontites 
  cooked 
  Marshall 
  90 
  

  

  In 
  conclusion 
  it 
  may 
  be 
  well 
  to 
  advise 
  those 
  who 
  wish 
  to 
  make 
  

   a 
  microscopic 
  examination 
  of 
  the 
  radiating 
  striae 
  in 
  the 
  Mutelidae 
  

   to 
  begin, 
  if 
  possible, 
  with 
  Diplodontites 
  cooJcei 
  Marshall, 
  then 
  take 
  

   Monocondylaea 
  franciscana 
  Moricand, 
  and 
  then 
  Anodontites 
  cris- 
  

   patus 
  Bruguiere, 
  passing 
  from 
  this 
  to 
  any 
  of 
  the 
  other 
  members 
  of 
  

   the 
  family. 
  The 
  species 
  mentioned 
  will 
  give 
  the 
  idea 
  of 
  what 
  to 
  

   look 
  for. 
  

  

  EXPLANATION 
  OF 
  PLATES 
  

  

  Plate 
  1 
  

  

  Fig. 
  1. 
  Anodontites 
  crispatus 
  Bruguiere. 
  At 
  posterior 
  portion 
  of 
  the 
  disk 
  X 
  

   30 
  diameters. 
  

  

  2. 
  Monocondylaca 
  franciscana 
  Moricand. 
  At 
  the 
  upper 
  portion 
  of 
  the 
  

  

  disk 
  X 
  50 
  diameters. 
  

  

  3. 
  Diplodontites 
  cookei 
  Marshall. 
  At 
  the 
  center 
  of 
  the 
  disk 
  X 
  50 
  diam- 
  

  

  eters. 
  

  

  Plate 
  2 
  

  

  All 
  figures 
  X 
  50 
  diameters 
  

  

  Fig. 
  1. 
  Monocondylaca 
  felipponei 
  Marshall. 
  Anterior 
  to 
  the 
  center 
  of 
  the 
  disk. 
  

  

  2. 
  Fossula 
  fossiculifera 
  Lea. 
  Anterior 
  to 
  the 
  center 
  of 
  the 
  disk. 
  

  

  3. 
  Anodontites 
  patagonicus 
  Lamarck. 
  Posterior 
  to 
  the 
  center 
  of 
  the 
  disk. 
  

  

  Plate 
  3 
  

   All 
  figures 
  X 
  50 
  diameters 
  

  

  Fig. 
  1. 
  Anodontitcs 
  tenebricosus 
  Lea. 
  At 
  the 
  upper 
  portion 
  of 
  the 
  disk. 
  

  

  2. 
  Anodontites 
  inaequivalvis 
  Lea. 
  On 
  the 
  dorsal 
  ridge. 
  

  

  3. 
  Anodontites 
  patagonicus 
  Lamarck. 
  High 
  up 
  on 
  the 
  disk. 
  

  

  