﻿852 
  FROCEEDIXaS 
  OF 
  THE 
  NATIONAL 
  MUSEUM. 
  vol.xx. 
  

  

  no 
  valid 
  excuse 
  for 
  applying 
  it 
  to 
  a 
  different 
  groui) 
  (Leda), 
  that 
  had 
  

   already 
  received 
  a 
  valid 
  name, 
  as 
  was 
  done 
  by 
  H. 
  and 
  A. 
  Adams. 
  

  

  That 
  a 
  species 
  belonging 
  to 
  Leda 
  was 
  mentioned 
  by 
  Link 
  does 
  not 
  

   alter 
  the 
  case, 
  lor 
  all 
  the 
  species 
  of 
  Leda 
  and 
  Yoldia 
  then 
  known 
  were 
  

   referred 
  to 
  Nucula 
  by 
  Lamarck 
  and 
  all 
  other 
  conchologists. 
  

  

  NUCULA 
  PROXIMA 
  Say, 
  variety 
  OVATA, 
  new. 
  

   (Plates 
  LXXXI, 
  fig. 
  P,; 
  LXXXVIII, 
  fig. 
  v,.) 
  

  

  We 
  designate 
  by 
  this 
  name 
  a 
  single 
  specimen 
  which 
  differs 
  so 
  widely 
  

   in 
  form 
  from 
  the 
  ordinary 
  type 
  of 
  J^ucnJa 
  proxima 
  that 
  it 
  could 
  Avell 
  

   be 
  taken 
  for 
  a 
  distinct 
  species 
  if 
  it 
  had 
  occurred 
  in 
  large 
  numbers 
  or 
  

   in 
  a 
  remote 
  locality. 
  It 
  is 
  broad-ovate 
  or 
  elliptical 
  in 
  form 
  and 
  much 
  

   less 
  angular 
  and 
  oblique 
  than 
  the 
  typical 
  proxima. 
  It 
  is 
  decidedly 
  

   compressed 
  with 
  the 
  umbos 
  much 
  less 
  prominent 
  than 
  usual. 
  The 
  

   surface 
  is 
  glossy, 
  grayish 
  white, 
  marked 
  with 
  distinct 
  lines 
  of 
  growth 
  

   and 
  microscopic 
  radiating 
  striic. 
  The 
  anterior 
  end 
  is 
  evenly 
  rounded 
  

   and 
  more 
  i^roduced 
  than 
  in 
  proxima; 
  the 
  ventral 
  margin 
  is 
  broadly 
  

   and 
  evenly 
  rounded; 
  the 
  posterior 
  end 
  is 
  obtuse, 
  slightly 
  produced 
  and 
  

   scarcely 
  augulated; 
  the 
  postero 
  dorsal 
  margin 
  is 
  convex 
  and 
  sloiies 
  

   much 
  less 
  rapidly 
  than 
  in 
  ji9ro.r*j« 
  a, 
  so 
  that 
  the 
  posterior 
  end 
  is 
  more 
  

   evenly 
  rounded 
  and 
  broader. 
  Internally 
  the 
  margin 
  is 
  plain. 
  The 
  

   hinge-teeth 
  are 
  much 
  as 
  va. 
  proxima, 
  but 
  the 
  two 
  series 
  are 
  less 
  curved 
  

   and 
  meet 
  in 
  a 
  broad 
  angle. 
  

  

  Length, 
  3.5 
  mm.; 
  height, 
  3 
  mm. 
  

  

  One 
  live 
  specimen 
  (l^o. 
  734G7), 
  station 
  8G3, 
  in 
  Vineyard 
  Sound, 
  off 
  

   Cutty 
  hunk, 
  in 
  IS 
  fathoms, 
  1880. 
  

  

  NUCULA 
  SUBOVATA, 
  new 
  species. 
  

   (Plates 
  LXXXI, 
  fig. 
  8; 
  LXXXIII, 
  fig. 
  5.) 
  

  

  Shell 
  small, 
  broad-ovate, 
  with 
  somewhat 
  i)rominent 
  umbos, 
  and 
  

   rather 
  acute, 
  somewhat 
  prominent 
  beaks 
  behind 
  the 
  middle. 
  Surface 
  

   smooth 
  and 
  lustrous, 
  covered 
  with 
  rather 
  regular, 
  concentric 
  lines 
  of 
  

   growth, 
  which 
  are 
  scarcely 
  visible 
  to 
  the 
  naked 
  eye. 
  Epidermis 
  thin, 
  

   pale 
  yellowish 
  green. 
  The 
  antero-dorsal 
  margin 
  is 
  nearly 
  straight 
  at 
  

   first; 
  then, 
  forming 
  a 
  convex 
  curve, 
  slopes 
  gradually 
  to 
  the 
  bluntly 
  

   rounded 
  anterior 
  end 
  which 
  is 
  somewhat 
  produced 
  but 
  not 
  angulated; 
  

   the 
  postero-dorsal 
  margin 
  is 
  convex, 
  sloping 
  rapidly, 
  and 
  forms 
  a 
  slight 
  

   rounded 
  angulation 
  in 
  the 
  middle 
  of 
  the 
  posterior 
  end, 
  where 
  it 
  joins 
  

   the 
  broadly 
  rounded, 
  ventral 
  margin. 
  Hinge-margin 
  rather 
  broad 
  and 
  

   strong 
  in 
  proportion 
  to 
  the 
  size 
  of 
  the 
  shell, 
  with 
  a 
  moderately 
  large 
  

   rounded, 
  slightly 
  oblique 
  chondrophore 
  projecting 
  considerably 
  within 
  

   the 
  margin. 
  The 
  portion 
  of 
  the 
  hinge-plate 
  behind 
  the 
  beaks 
  is 
  con- 
  

   siderably 
  shorter 
  than 
  that 
  in 
  front 
  and 
  bears 
  about 
  six, 
  strong, 
  

   V-shaped 
  teeth 
  of 
  which 
  the 
  two 
  distal 
  ones 
  and 
  the 
  two 
  proximal 
  ones 
  

   are 
  much 
  smaller 
  thau 
  the 
  others; 
  in 
  front 
  of 
  the 
  beaks 
  it 
  is 
  broad 
  and 
  

  

  