﻿384 
  

  

  Prof. 
  T. 
  R. 
  Jones 
  on 
  the 
  

  

  (Ann. 
  & 
  Mag. 
  Nat. 
  Hist. 
  April 
  1858, 
  p. 
  245, 
  pi. 
  ix. 
  fig. 
  3), 
  

   which, 
  however, 
  has 
  the 
  eye-spot 
  and 
  ventral 
  overlap. 
  

  

  It 
  seems 
  not 
  to 
  have 
  been 
  thickened 
  on 
  the 
  ventral 
  mar- 
  

   gin 
  nor 
  to 
  have 
  overlapped 
  there. 
  No 
  external 
  structural 
  

   marks 
  are 
  visible, 
  but 
  they 
  may 
  have 
  been 
  obliterated 
  by 
  

   fossilization, 
  for 
  the 
  surface 
  of 
  the 
  valve 
  is 
  roughened 
  by 
  

   minute 
  accretions. 
  The 
  ends 
  have 
  broad 
  rims, 
  and 
  so 
  might 
  

   the 
  ventral 
  margin 
  have 
  also 
  been 
  flanged, 
  but 
  the 
  convexity 
  

   of 
  the 
  ventral 
  region 
  overhangs, 
  and 
  the 
  matrix 
  hides 
  it, 
  if 
  

   at 
  all 
  preserved. 
  

  

  In 
  greenish-grey 
  calcareous 
  shale 
  like 
  that 
  of 
  other 
  speci- 
  

   mens 
  from 
  Cap 
  Bon-Ami. 
  

  

  Fisr. 
  3. 
  

  

  Fig. 
  4. 
  

  

  Fios. 
  3 
  and 
  4. 
  — 
  Isochilina 
  labrosa, 
  nov., 
  magnified 
  10 
  diameters. 
  

  

  3. 
  Front 
  end 
  view. 
  4. 
  Ventral 
  view. 
  

  

  [See 
  Plate 
  XVIT. 
  fig. 
  11.] 
  

  

  III. 
  Specimen 
  from 
  Manitoba. 
  

  

  8. 
  Aparchites* 
  Whiteavesii. 
  

   (PI. 
  XVII. 
  fig. 
  10, 
  and 
  woodcuts, 
  figs. 
  5 
  and 
  6.) 
  

  

  Other 
  Ostracoda 
  than 
  those 
  mentioned 
  above, 
  at 
  p. 
  383, 
  

   somewhat, 
  but 
  not 
  quite, 
  Leperditian 
  in 
  outline 
  and 
  contour, 
  

   the 
  dorsal 
  angles 
  being 
  nearly 
  or 
  quite 
  absent, 
  are 
  generally 
  

   much 
  smaller 
  than 
  the 
  above-mentioned 
  forms, 
  and 
  are 
  with- 
  

   out 
  either 
  ocular 
  or 
  muscular 
  spot, 
  and 
  have 
  no 
  overlap 
  on 
  

   the 
  ventral 
  margin, 
  though 
  sometimes 
  thickened 
  there. 
  Some 
  

   such 
  Ostracods, 
  but 
  of 
  relatively 
  large 
  size, 
  were 
  described 
  

   and 
  figured 
  in 
  the 
  Ann. 
  & 
  Mag. 
  Nat. 
  Hist. 
  ser. 
  3, 
  vol. 
  xvi. 
  

   1865, 
  pi. 
  xiii. 
  figs. 
  7, 
  10, 
  12-14, 
  and 
  ser. 
  4, 
  vol. 
  ii. 
  1868, 
  

   pi. 
  vii. 
  figs. 
  1-4, 
  as 
  Primitice 
  ; 
  and 
  P. 
  solvensis 
  [op. 
  cit. 
  

  

  * 
  From 
  dnapxr), 
  primitia. 
  

  

  