﻿Derbyina 
  smithi 
  (Derby) 
  

  

  Fig. 
  i, 
  2 
  Copies 
  of 
  Derby's 
  figures 
  of 
  the 
  brachial 
  apparatus 
  

   3 
  Ventral 
  side 
  of 
  an 
  internal 
  cast, 
  x 
  2 
  

   4, 
  5, 
  6 
  Ventral 
  profile 
  and 
  dorsal 
  views 
  of 
  an 
  internal 
  cast, 
  

   x 
  2 
  

   Locality: 
  Ponta 
  Grossa, 
  Brazil 
  

  

  Paranaia 
  margarida 
  (Derby) 
  

  

  Fig. 
  7, 
  8 
  Derby's 
  figures 
  of 
  the 
  brachial 
  apparatus 
  

  

  Locality: 
  Sant'Ana 
  de 
  Chapada, 
  Mato 
  Grosso, 
  Brazil 
  

  

  Cryptonella 
  ? 
  baini 
  (Sharpe) 
  

  

  Fig. 
  9 
  Cast 
  of 
  ventral 
  valve 
  

  

  10, 
  11 
  Dorsal 
  views 
  of 
  internal 
  casts 
  

  

  12 
  Dorsal 
  valve 
  with 
  hinge 
  plate 
  

  

  13 
  Enlargement 
  of 
  the 
  surface 
  of 
  an 
  inside 
  cast, 
  showing 
  

  

  the 
  filling 
  of 
  the 
  shell 
  punctures 
  

   Locality: 
  Tybagy, 
  Sao 
  Paulo, 
  Brazil 
  

  

  Rensselaeria 
  falklandica 
  Clarke 
  

  

  Fig. 
  14 
  Internal 
  cast 
  of 
  ventral 
  valve 
  

   15 
  Dorsal 
  view 
  of 
  an 
  internal 
  cast 
  

  

  Locality: 
  Port 
  Flo 
  ward, 
  East 
  Falkland 
  

  

  182 
  

  

  