﻿190 
  

  

  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  m 
  

  

  Fig. 
  101 
  Anastrophiainter- 
  

   plicata 
  

  

  

  Fig. 
  lOa 
  Anastrophla 
  breviroslris 
  

  

  Anastrophia 
  mterplicata 
  (Hall) 
  (Fig. 
  loi). 
  Atrypa 
  inter- 
  

   plica 
  t 
  a 
  Hall 
  (1852. 
  Pal 
  N. 
  Y. 
  2\2ys, 
  pL 
  57) 
  

   Distinguishing 
  characters. 
  Extremely 
  con- 
  

   vex; 
  brachial 
  valve 
  the 
  deepest; 
  moderate 
  sinus 
  

   and 
  fold; 
  from 
  two 
  to 
  three 
  plications 
  in 
  the 
  

   former 
  and 
  three 
  to 
  four 
  on 
  the 
  latter; 
  lateral 
  

   plications 
  increase 
  by 
  implantation. 
  

  

  Found 
  in 
  the 
  Clinton 
  lenses, 
  and 
  in 
  the 
  lower 
  

   and 
  middle 
  Rochester 
  shale 
  at 
  Niagara. 
  Also 
  in 
  the 
  shale 
  at 
  

   Lockport 
  (Hall). 
  

  

  Anastrophia 
  brevirostris 
  Hall 
  (Fig. 
  

   102) 
  Atrypa 
  brevirostris 
  

   Hall 
  (1852. 
  Pal 
  N. 
  F. 
  2:278, 
  pi. 
  58) 
  

   Distinguishing 
  characters. 
  Wider 
  

   than 
  high; 
  strongly 
  convex; 
  brachial 
  

   valve 
  deepest; 
  short 
  nearly 
  equal 
  beaks; 
  

   sharp 
  bifurcating 
  or 
  interpolated 
  plica- 
  

   tions, 
  from 
  five 
  to 
  six 
  in 
  the 
  sinus 
  and 
  fold, 
  which 
  are 
  broad 
  and 
  ill 
  

   defined. 
  

  

  Found 
  in 
  the 
  lower 
  Rochester 
  shale 
  at 
  Niagara 
  (?). 
  Also 
  in 
  the 
  

   shale 
  at 
  Lockport 
  (Hall). 
  

  

  Genus 
  pentamerus 
  Sowerby 
  

   [Ety. 
  : 
  -^vTc, 
  five; 
  !J.ipo<;, 
  part] 
  

   (1813. 
  Sowerby. 
  M/ncra/ 
  co/zc/z^/o^j', 
  1 
  176; 
  Hall 
  & 
  Clarke. 
  1893. 
  

   Pal 
  N. 
  Y. 
  V. 
  8, 
  pt 
  2, 
  p. 
  22,6) 
  

  

  Shell 
  strongly 
  inequivalve, 
  biconvex 
  with 
  highly 
  arched 
  pedicle 
  

   valve; 
  surface 
  smooth, 
  or 
  with 
  a 
  few 
  broad 
  and 
  obscure 
  radiating 
  

   undulations. 
  Under 
  the 
  beak 
  of 
  the 
  pedicle 
  valve 
  is 
  a 
  deep 
  and 
  

   narrow 
  spondylium, 
  or 
  plate 
  with 
  an 
  excavated 
  spoon-shaped 
  cavity, 
  

   supported 
  by 
  a 
  high 
  vertical 
  septum 
  of 
  variable 
  length; 
  brachial 
  

   valve 
  with 
  a 
  pair 
  of 
  septa, 
  the 
  interior 
  of 
  the 
  shell 
  being 
  thus 
  di- 
  

   vided 
  into 
  five 
  compartments. 
  

  

  Pentamerus 
  oblongus 
  Sowerby 
  (Fig. 
  103) 
  (Hall. 
  1852. 
  Pal 
  

   N. 
  Y. 
  2:79, 
  Pl- 
  25) 
  

  

  Distinguishing 
  characters. 
  Very 
  large 
  and 
  oblong, 
  varying 
  in 
  out- 
  

   line 
  with 
  age; 
  wider 
  in 
  anterior 
  part; 
  valves 
  strongly 
  convex 
  at 
  

   beaks; 
  beak 
  of 
  pedicle 
  valve 
  overarching; 
  subtrilobate 
  division 
  of 
  

  

  