﻿Derbyina 
  whitiorum 
  Clarke 
  

  

  Fig. 
  i, 
  

  

  3 
  Enlargement 
  of 
  ventral 
  hinge 
  

  

  4 
  A 
  dorsal 
  valve 
  

  

  Locality: 
  Ponta 
  Grossa, 
  Brazil 
  

  

  Leptocoelia 
  flabellites 
  (Conrad) 
  

  

  Fig. 
  5 
  Exterior 
  of 
  an 
  average 
  adult 
  specimen 
  

  

  6 
  A 
  dorsal 
  valve 
  

  

  7 
  Internal 
  cast 
  of 
  large 
  ventral 
  valve 
  

   Locality: 
  Ponta 
  Grossa, 
  Brazil 
  

  

  8 
  Internal 
  cast 
  of 
  dorsal 
  valve 
  

   Locality: 
  Jaguariahyva, 
  Brazil 
  

  

  9 
  Dorsal 
  cast 
  

  

  Locality: 
  Cold 
  Bokkeveld, 
  Cape 
  Colony 
  

  

  Coelospira 
  ? 
  colona 
  Clarke 
  

  

  Fig. 
  io, 
  ii 
  Ventral 
  valves, 
  x 
  2 
  

  

  12, 
  13 
  Ventral 
  and 
  dorsal 
  views, 
  x 
  2 
  

   Locality: 
  Ponta 
  Grossa, 
  Brazil 
  

  

  Leptostrophia 
  ?? 
  mesembria 
  Clarke 
  

  

  Fig. 
  14 
  Exterior 
  of 
  ventral 
  with 
  internal 
  cast 
  of 
  dorsal 
  valve 
  

  

  15 
  Sculpture 
  cast 
  showing 
  dorsal 
  aspect 
  

   Locality: 
  Fox 
  bay, 
  West 
  Falkland 
  

  

  16 
  Enlargement 
  of 
  hinge 
  structure 
  showing 
  incipient 
  denti- 
  

  

  cles 
  or 
  spinules 
  on 
  cardinal 
  line 
  

  

  17 
  Internal 
  cast 
  of 
  ventral 
  valve 
  

   Locality: 
  Ponta 
  Grossa, 
  Brazil 
  

  

  18 
  Internal 
  ventral 
  cast 
  

   Locality: 
  Jaguariahyva, 
  Brazil 
  

  

  194 
  

  

  