﻿1056 
  Forty- 
  seventh 
  Report 
  on 
  the 
  State 
  Museum. 
  

  

  valve, 
  and 
  the 
  recurvature 
  of 
  the 
  ascending 
  branches 
  exceedingly 
  

   slight. 
  This 
  recurved 
  lamella 
  is 
  so 
  delicate 
  that 
  it 
  is 
  rarely 
  com- 
  

   pletely 
  preserved, 
  but 
  when 
  retained, 
  the 
  entire 
  brachidium 
  has 
  

  

  Fig. 
  496. 
  Fig. 
  497. 
  

  

  Fig. 
  496. 
  Eunella 
  simulator, 
  Hall; 
  showing 
  the 
  character 
  of 
  the 
  hinge-plate, 
  the 
  relative 
  length 
  

  

  and 
  usual 
  preservation 
  of 
  the 
  brachidium, 
  with 
  the 
  ascending 
  band 
  lost. 
  

   Fig. 
  497. 
  Eunella 
  Sullivanti, 
  Hall; 
  a 
  dorsal 
  view 
  of 
  the 
  complete 
  brachidium. 
  

  

  the 
  form 
  represented 
  in 
  the 
  adjoining 
  figure. 
  The 
  crural 
  

   apophyses 
  are 
  situated 
  more 
  anteriorly 
  than 
  in 
  Cryptonella 
  and 
  

   are 
  much 
  broader 
  at 
  the 
  base. 
  

  

  Type, 
  Eunella 
  Sullivanti, 
  Hall 
  (sp.). 
  Devonian. 
  

  

  Harttina, 
  Hall. 
  1893. 
  

   (Plate 
  52, 
  figs. 
  29-31.) 
  

  

  Shells 
  plano-convex 
  or 
  naviculoid 
  ; 
  brachial 
  valve 
  depressed 
  - 
  

   convex 
  or 
  nearly 
  flat 
  and 
  the 
  pedicle- 
  valve 
  medially 
  ridged 
  with 
  

   abrupt 
  slopes 
  at 
  the 
  sides. 
  Dental 
  lamellae 
  of 
  the 
  pedicle-valve 
  

   well 
  developed. 
  In 
  the 
  brachial 
  valve 
  there 
  is 
  a 
  short, 
  tripartite 
  

   hinge-plate, 
  supported 
  by 
  a 
  median 
  septum 
  of 
  considerable 
  height 
  

   in 
  the 
  umbonal 
  region 
  and 
  extending 
  for 
  fully 
  one-half 
  the 
  length 
  

   of 
  the 
  valve, 
  becoming 
  low 
  anteriorly. 
  

  

  The 
  crura 
  are 
  very 
  short 
  and 
  are 
  continued 
  almost 
  immediately 
  

   into 
  the 
  long 
  convergent 
  crural 
  apophyses. 
  The 
  descending 
  

   branches 
  of 
  the 
  brachidium 
  extend 
  for 
  nearly 
  the 
  entire 
  length 
  

   of 
  the 
  shell, 
  following 
  the 
  curvature 
  of 
  the 
  valve 
  and 
  approach- 
  

   ing 
  each 
  other 
  anteriorly, 
  their 
  extremities 
  being 
  again 
  directed 
  

   outward. 
  The 
  ascending 
  branches 
  extend 
  backward 
  to 
  points 
  

   not 
  far 
  in 
  front 
  of 
  the 
  crural 
  apophyses, 
  where 
  they 
  are 
  united 
  

   by 
  a 
  transverse 
  band. 
  The 
  outer 
  margins 
  of 
  the 
  descending 
  

  

  114 
  

  

  