﻿24 
  

  

  PROCEEDINGS 
  OF 
  THE 
  MALACOLOGICAL 
  SOCIETY. 
  

  

  a 
  thin, 
  pale, 
  olivaceous 
  periostracum, 
  which 
  is 
  more 
  apparent 
  towards 
  

   the 
  outer 
  margin 
  than 
  at 
  the 
  umbones. 
  The 
  surface 
  exhibits 
  fine 
  yet 
  

   (piite 
  distinct 
  lines 
  of 
  growth, 
  radiating 
  series 
  of 
  minute 
  granu- 
  

   lations 
  towards 
  the 
  umbones, 
  and 
  faint 
  traces 
  of 
  radiating 
  sculpture 
  

   upon 
  the 
  rest 
  of 
  the 
  valves. 
  In 
  form 
  they 
  rather 
  resemble 
  Mya 
  

   truncata 
  in 
  miniature, 
  being 
  somewhat 
  quadrate, 
  obliquely 
  truncate 
  

   behind, 
  and 
  more 
  rounded 
  in 
  front. 
  The 
  beaks, 
  although 
  minute, 
  

   terminate 
  in 
  a 
  white 
  rounded 
  boss 
  ; 
  they 
  are 
  contiguous, 
  and 
  inclined 
  

   slightly 
  anteriorly. 
  The 
  anterior 
  dorsal 
  margin 
  is 
  obliquely 
  excurved, 
  

   the 
  posterior 
  being 
  parallel 
  with 
  the 
  ventral, 
  but 
  slightly 
  incurved. 
  

   The 
  hinge 
  is 
  edentate, 
  and 
  consists 
  merely 
  of 
  a 
  ligament 
  attached 
  

   just 
  below 
  the 
  extreme 
  margin 
  of 
  the 
  valves 
  posterior 
  to 
  the 
  umbones. 
  

   This 
  ligament 
  has 
  a 
  distinct 
  shelly 
  lining 
  which 
  is 
  slightly 
  convex 
  

   on 
  the 
  underside, 
  truncate, 
  and 
  broad 
  at 
  the 
  hinder 
  end, 
  and 
  narrowed 
  

   in 
  front. 
  Interior 
  of 
  the 
  valves 
  white, 
  almost 
  silvery, 
  concentrically 
  

   wrinkled 
  here 
  and 
  there. 
  

  

  The 
  body 
  of 
  the 
  animal 
  is 
  enclosed 
  in 
  a 
  sack-like 
  mantle, 
  is 
  soft, 
  

   ovate-globose, 
  terminating 
  posteriorly 
  in 
  a 
  thin 
  whip-like 
  process. 
  The 
  

   surface 
  of 
  the 
  swollen 
  part 
  exhibits 
  a 
  sort 
  of 
  reticulation 
  which 
  may 
  

   be 
  merely 
  the 
  wrinkling 
  of 
  the 
  delicate 
  outer 
  skin. 
  Also 
  numerous 
  

   siliceous 
  particles 
  are 
  adherent 
  to 
  the 
  surface. 
  This, 
  however, 
  is 
  

   probably 
  only 
  an 
  accidental 
  feature. 
  Two 
  openings 
  are 
  observable, 
  

   both 
  apparently 
  ventral, 
  judging 
  by 
  the 
  position 
  of 
  the 
  shell. 
  The 
  

   anterior, 
  situated 
  between 
  the 
  ventral 
  margins 
  of 
  the 
  valve, 
  is 
  narrow 
  

   and 
  elongate. 
  The 
  posterior 
  is 
  at 
  the 
  other 
  end 
  of 
  the 
  body, 
  near 
  the 
  

   commencement 
  of 
  the 
  slender 
  prolongation. 
  It 
  appears 
  to 
  be 
  small 
  

  

  