﻿1096 
  Forty-seventh 
  Report 
  on 
  the 
  State 
  Museum. 
  

  

  External 
  surface 
  covered 
  with 
  flexuous 
  lines 
  of 
  growth. 
  

   Shell-substance 
  punctate 
  in 
  the 
  inner 
  layers. 
  

   Type, 
  Lyttonia 
  nobilis, 
  Waagen. 
  

   Distribution. 
  Carboniferous. 
  

  

  Oldhamina, 
  Waagen. 
  1883. 
  

  

  Shells 
  highly 
  concavo-convex. 
  

  

  Pedicle-valve 
  subhemispherical 
  ; 
  apex 
  incurved, 
  at 
  maturity 
  

   covered 
  by 
  a 
  callosity, 
  as 
  in 
  Bellerophon 
  ; 
  attached 
  by 
  cementa- 
  

   tion 
  in 
  early 
  growth. 
  Hinge-line 
  short 
  and 
  straight, 
  not 
  inter- 
  

   rupted 
  in 
  the 
  middle 
  ; 
  below 
  it 
  lie 
  well-developed 
  teeth. 
  Interior 
  

   surface 
  of 
  the 
  valve 
  covered 
  with 
  diverging 
  lateral 
  ridges. 
  

  

  Brachial 
  valve 
  concave. 
  Cardinal 
  process 
  inconspicuous, 
  quad- 
  

   ripartite 
  at 
  the 
  summit 
  ; 
  continuous 
  with 
  a 
  median 
  ridge 
  extend- 
  

  

  Fig. 
  657. 
  

  

  Fig. 
  658. 
  

  

  Oldhamina 
  decipiens, 
  de 
  Koninck. 
  

  

  Fig. 
  657. 
  The 
  interior 
  of 
  a 
  pedicle- 
  valve; 
  showing 
  the 
  median 
  and 
  lateral 
  ridges. 
  

   Fig. 
  658. 
  The 
  exterior 
  of 
  a 
  pedicle-valve 
  with 
  the 
  shell 
  partly 
  exfoliated. 
  (Waagen.) 
  

  

  ing 
  the 
  entire 
  length 
  of 
  the 
  valve. 
  Internal 
  surface 
  covered 
  with 
  

   divergent 
  grooves 
  corresponding 
  to 
  the 
  ridges 
  of 
  the 
  opposite 
  

   valve. 
  

  

  Exterior 
  smooth 
  or 
  with 
  numerous 
  concentric 
  lines 
  of 
  growth. 
  

  

  Type, 
  Oldhamina 
  decipiens, 
  de 
  Koninck 
  (sp.). 
  

  

  Distribution. 
  Carboniferous. 
  

  

  154 
  

  

  