﻿2l8 
  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  apical 
  angle 
  of 
  spire 
  about 
  60° 
  ; 
  fine 
  crowded 
  surface 
  striae. 
  In 
  the 
  

   specimens 
  so 
  far 
  obtained 
  from 
  the 
  Manlius 
  Hmestone, 
  no 
  septa 
  have 
  

   been 
  preserved. 
  

  

  Found 
  in 
  the 
  Manlius 
  limestone 
  of 
  North 
  Buffalo 
  (Vogt 
  & 
  Piper^ 
  

   fig. 
  149) 
  and 
  Williamsville. 
  The 
  species 
  was 
  originally 
  described 
  

   from 
  the 
  Coralline 
  limestone 
  (Niagara) 
  of 
  Schoharie 
  county 
  (N. 
  Y.) 
  

  

  Class 
  CRUSTACEA 
  Lamarck 
  

  

  Order 
  ostr^vcod^v 
  Latr, 
  

  

  The 
  ostracods 
  are 
  small 
  Crustacea, 
  with 
  a 
  bivalve, 
  calcareous 
  or 
  

   horny 
  shell 
  covering 
  the 
  entire 
  body. 
  The 
  valves 
  are 
  joined 
  dorsally 
  

   by 
  a 
  membrane, 
  and 
  open 
  alon^ 
  the 
  ventral 
  side. 
  The 
  body 
  is 
  in- 
  

   distinctly 
  segmented, 
  and 
  bears 
  seven 
  pairs 
  of 
  appendages, 
  two 
  

   pairs 
  of 
  which 
  represent 
  the 
  trunk 
  limbs. 
  The 
  shell 
  corresponds 
  

   to 
  the 
  carapace 
  of 
  the 
  higher 
  crustaceans. 
  These 
  organisms 
  are 
  

   minute 
  and 
  will 
  ordinarily 
  be 
  overlooked 
  unless 
  search 
  is 
  made 
  for 
  

   them 
  with 
  a 
  lens 
  on 
  the 
  surfaces 
  of 
  the 
  shale 
  laminae. 
  They 
  are 
  

   specially 
  abundant 
  in 
  the 
  finer 
  grained 
  shales. 
  

  

  Genus 
  isochilina 
  Jones 
  

  

  [Ety. 
  : 
  l'(7()?, 
  equal 
  to; 
  xeiXo?, 
  lip] 
  

  

  (1858. 
  Can. 
  organic 
  remains, 
  Decade 
  3, 
  p. 
  197) 
  

  

  Carapace 
  with 
  equal 
  valves, 
  whose 
  margins 
  meet 
  uniformly 
  and 
  

   do 
  not 
  overlap; 
  greatest 
  convexity 
  central, 
  or 
  toward 
  the 
  anterior 
  

   end; 
  anterior 
  tubercle 
  present. 
  

  

  Isochilina 
  cylindrica 
  (Hall). 
  Cytherina 
  cylindrica 
  Hall 
  

   (1852. 
  Pal. 
  N. 
  Y. 
  2:14, 
  pi. 
  4) 
  

  

  Distinguishing 
  characters. 
  Oval, 
  elongate 
  form; 
  great 
  convexity, 
  

   " 
  which, 
  when 
  both 
  valves 
  are 
  joined, 
  would 
  give 
  an 
  almost 
  cylin- 
  

   drical 
  form 
  to 
  the 
  shell 
  ". 
  

  

  Found 
  in 
  the 
  upper 
  Medina 
  sandstones 
  at 
  Medina 
  (Hall), 
  but 
  

   probably 
  also 
  at 
  Niagara 
  and 
  other 
  places. 
  

  

  Genus 
  leperditia 
  Rouault 
  

  

  [Ety.: 
  Leperdit, 
  proper 
  name] 
  

  

  (185 
  1. 
  Soc. 
  geol. 
  France. 
  Bui. 
  ser. 
  2, 
  8:377) 
  

  

  Carapace 
  with 
  unequal 
  valves, 
  the 
  right 
  valve 
  the 
  larger 
  and 
  over- 
  

   lapping 
  the 
  left 
  valve, 
  along 
  the 
  ventral 
  and, 
  to 
  some 
  extent, 
  along 
  

   the 
  anterior 
  and 
  posterior 
  ends; 
  valves 
  smooth, 
  oblong 
  and 
  horny. 
  

  

  