﻿148 
  Twenty-eighth 
  Report 
  on" 
  the 
  State 
  Museum. 
  

  

  BRACHIOPODA. 
  

  

  CRANIA 
  Lamarck. 
  

   Ceanta 
  Sllueiana. 
  . 
  

  

  Plate 
  21, 
  Figs 
  3-7. 
  

  

  Crania 
  Siluriana 
  Hall. 
  Trans. 
  Alb. 
  Inst., 
  vol. 
  iv 
  p. 
  208. 
  Abstract 
  p. 
  14; 
  May, 
  

  

  1863. 
  

   Compare 
  Crania 
  Siluriana 
  Davidson. 
  "British 
  Brachiopoda, 
  " 
  Part 
  vii, 
  No. 
  1, 
  

  

  pi. 
  8, 
  figs. 
  19, 
  20. 
  1866. 
  

  

  Shell 
  subcircular 
  or 
  transverse, 
  very 
  depressed-conical, 
  

   apex 
  excentric, 
  slightly 
  curved, 
  situated 
  one-third 
  the 
  diam- 
  

   ter 
  of 
  the 
  shell 
  from 
  the 
  cardinal 
  border. 
  Exterior 
  surface 
  of 
  

   upper 
  valve 
  smooth, 
  with 
  concentric 
  lines 
  of 
  growth. 
  

   Yentral 
  or 
  lower 
  valve 
  consisting 
  of 
  little 
  more 
  than 
  a 
  thick- 
  

   ened 
  rim, 
  deeply 
  marked 
  on 
  the 
  cardinal 
  margin 
  by 
  the 
  some- 
  

   what 
  large, 
  distant, 
  posterior, 
  adductor, 
  muscular 
  scars 
  ; 
  the 
  

   substance 
  within 
  the 
  thickened 
  border, 
  not 
  sufficient 
  to 
  pre- 
  

   serve 
  the 
  muscular 
  or 
  vascular 
  markings. 
  

  

  Transverse 
  diameter 
  of 
  full 
  grown 
  specimens 
  nearly 
  20 
  mm.; 
  

   height 
  of 
  upper 
  valve 
  of 
  the 
  same 
  a 
  little 
  less 
  than 
  6 
  mm. 
  

   Where 
  well 
  preserved 
  the 
  surface 
  is 
  minutely 
  granulose 
  or 
  

   subpunctate. 
  

  

  This 
  species 
  is 
  usually 
  found 
  adhering 
  to 
  other 
  fossils 
  which 
  

   are 
  in 
  a 
  more 
  or 
  less 
  dilapidated 
  condition 
  ; 
  showing 
  that 
  the 
  

   Cranise 
  became 
  attached 
  after 
  the 
  death 
  of 
  the 
  individuals 
  on 
  

   which 
  they 
  are 
  found. 
  

  

  Cbania 
  setifeea. 
  

  

  Plate 
  21, 
  Figs 
  8-10. 
  

  

  Crania 
  setifera 
  Hall. 
  Trans. 
  Alb. 
  Inst., 
  vol. 
  iv, 
  p. 
  209. 
  Abstract 
  p. 
  15; 
  May, 
  1863. 
  

   (In 
  error) 
  C. 
  setigera 
  Hall. 
  Doc. 
  Edit. 
  28th 
  Eep. 
  St. 
  Mus. 
  Nat. 
  Hist. 
  Explana- 
  

   tion 
  of 
  pi. 
  21, 
  figs. 
  8-10. 
  1876. 
  

  

  Shell 
  circular, 
  depressed-convex, 
  apex 
  central 
  or 
  slightly 
  

   excentric, 
  small, 
  pointed 
  or 
  mammiform. 
  Surface 
  of 
  upper 
  

  

  