﻿1094 
  Forty-seventh 
  Report 
  on 
  the 
  State 
  Museum. 
  

  

  Eudesella, 
  Munier-Chalmas. 
  1880. 
  

  

  Shells 
  transverse, 
  with 
  long, 
  straight 
  hinge. 
  Cardinal 
  area 
  and 
  

   deltidium 
  well 
  developed. 
  Pedicle-valve 
  moderately 
  deep; 
  

  

  muscular 
  scars 
  posterior 
  and 
  thick- 
  

   ened. 
  Divisions 
  of 
  the 
  internal 
  

   surface 
  corresponding 
  to 
  those 
  of 
  

   the 
  opposite 
  valve. 
  Brachial 
  valve 
  

   flat 
  ; 
  cardinal 
  process 
  prominent, 
  

   subrectangular. 
  Median 
  septum 
  

   extending 
  from 
  the 
  anterior 
  

   border 
  to 
  the 
  cardinal 
  region 
  ; 
  

   two 
  shorter 
  lateral 
  septa 
  lie 
  on 
  

   each 
  side. 
  Brachial 
  lamellae 
  following 
  the 
  lobes 
  formed 
  by 
  the 
  

   septa. 
  

  

  Type, 
  Eudesella 
  May 
  alls, 
  Deslongchamps 
  (sp.). 
  

   Distribution. 
  Lias. 
  

  

  Fig 
  651 
  Eudesella 
  Mayalis, 
  Deslong 
  

   champs 
  (sp 
  ) 
  (GEhlert.) 
  

  

  Bactrynium, 
  Emmrich, 
  1855. 
  

  

  Synonym; 
  Pterophloios, 
  Giimbel. 
  1861. 
  

  

  Shells 
  elongate, 
  plano-convex 
  ; 
  attached 
  by 
  the 
  apex 
  of 
  the 
  

  

  pedicle- 
  valve. 
  Surface 
  smooth 
  or 
  with 
  concentric 
  striae. 
  Shell 
  

  

  substance 
  punctate. 
  Pedicle-valve 
  highly 
  convex. 
  

  

  On 
  the 
  interior 
  is 
  a 
  low 
  median 
  septum 
  in 
  the 
  urn- 
  

  

  bonal 
  region 
  In 
  the 
  brachial 
  valve 
  the 
  cardinal 
  

  

  process 
  is 
  well 
  developed. 
  The 
  median 
  septum 
  

  

  begin* 
  near 
  the 
  anterior 
  margin 
  of 
  the 
  shell 
  and 
  

  

  fig. 
  652. 
  Bac- 
  ex 
  f 
  enc 
  [ 
  s 
  backward 
  almost 
  to 
  the 
  base 
  of 
  the 
  cardinal 
  

  

  trymum 
  Emm- 
  

  

  ricM, 
  Gtimbei. 
  process. 
  On 
  each 
  side 
  are 
  from 
  eight 
  to 
  ten 
  short 
  

   (Hcernes) 
  transverse 
  or 
  convergent 
  septa, 
  together 
  forming 
  

  

  a 
  series 
  of 
  lobes 
  which 
  are 
  bounded 
  by 
  the 
  brachial 
  lamella. 
  

  

  Type, 
  Bactrynium 
  Mnmrichi, 
  Gtimbei 
  (sp.). 
  

  

  Distribution. 
  Lias. 
  

  

  Davidsonella, 
  Munier-Chalmas. 
  1880. 
  

  

  Shells 
  small, 
  plano-convex, 
  elongate 
  or 
  subquadrangular 
  ; 
  

   attached 
  by 
  the 
  umbo 
  of 
  the 
  pedicle- 
  valve 
  which 
  may 
  thereby 
  

   become 
  deformed 
  or 
  truncated. 
  Cardinal 
  area 
  and 
  deltidium 
  

   well 
  developed. 
  Pedicle-valve 
  with 
  two 
  strong, 
  approximate 
  

   teeth 
  ; 
  subcardinal 
  muscular 
  plate 
  divided 
  by 
  a 
  vertical 
  lamella 
  

  

  152 
  

  

  