﻿808 
  rBOCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM. 
  

  

  although 
  the 
  elevation 
  and 
  distance 
  between 
  them 
  gradually 
  increase 
  

   posteriorly, 
  while 
  in 
  the 
  former 
  they 
  are 
  broadly 
  rounded 
  and 
  separated 
  

   for 
  the 
  most 
  part 
  by 
  narrow 
  interstices. 
  The 
  hinge 
  also 
  differs 
  consid- 
  

   erably; 
  the 
  cartilage-plate 
  is 
  less 
  prominent 
  and 
  broader 
  than 
  that 
  of 
  

   multicofitata, 
  and 
  the 
  tooth 
  in 
  the 
  right 
  valve 
  is 
  longer 
  and 
  not 
  so 
  

   prominent 
  and 
  scarcely 
  forms 
  a 
  notch 
  at 
  its 
  junction 
  with 
  the 
  cartilage- 
  

   plate; 
  anteriorly 
  the 
  margin 
  is 
  very 
  thin 
  and 
  simple 
  with 
  a 
  very 
  nar- 
  

   row, 
  linear, 
  ligamental 
  groove 
  along 
  its 
  outer 
  edge, 
  while 
  in 
  the 
  former 
  

   the 
  groove 
  is 
  broader 
  and 
  its 
  inner 
  edge 
  is 
  raised 
  almost 
  in 
  the 
  form 
  of 
  

   a 
  lateral 
  tooth. 
  

  

  It 
  also 
  resembles 
  C. 
  costelJata 
  var. 
  corpulenta 
  Dall 
  in 
  the 
  character 
  

   of 
  the 
  cost*, 
  but 
  the 
  latter 
  is 
  much 
  shorter 
  and 
  higher 
  in 
  form 
  and 
  has 
  

   a 
  very 
  short, 
  ill-defined 
  rostrum. 
  

  

  Two 
  young 
  live 
  specimens, 
  two 
  separate 
  valves, 
  and 
  some 
  fragments 
  

   were 
  taken 
  at 
  three 
  stations, 
  between 
  N. 
  lat. 
  40° 
  29', 
  W. 
  long. 
  66° 
  14', 
  

   and 
  N. 
  lat. 
  36° 
  47', 
  W. 
  long. 
  73° 
  9' 
  30", 
  in 
  1,685 
  to 
  1,813 
  fathoms, 
  1885-86. 
  

  

  CARDIOMYA 
  MULTICOSTATA 
  Verrill 
  and 
  Smith. 
  

  

  (Plate 
  LXXIII, 
  fig. 
  3.) 
  

  

  Ne(v,ra 
  mnUicostata 
  Verrill, 
  Trans. 
  Conn. 
  Acad., 
  V, 
  p. 
  559, 
  pi. 
  LViii, 
  fig. 
  40, 
  1882; 
  

  

  VI, 
  p. 
  277, 
  1884; 
  Expl. 
  Alhatross, 
  Eeport 
  TI. 
  S. 
  Com. 
  Fish 
  and 
  Fisheries 
  for 
  

  

  1883, 
  pi. 
  XXX, 
  fig. 
  129, 
  1885.— 
  Smith, 
  E. 
  A., 
  Report 
  Voy. 
  Challenger, 
  Zool. 
  

  

  Lamellibranchiata, 
  XIII, 
  p. 
  36, 
  1885. 
  

   Not 
  Cardiomya 
  striata 
  Dall, 
  Bull. 
  Mus. 
  Comp. 
  Zoiil., 
  XII, 
  p. 
  298, 
  pi. 
  iii, 
  fig. 
  10, 
  

  

  1886; 
  Bull. 
  U. 
  8. 
  Nat. 
  Mus., 
  No. 
  37, 
  p. 
  66, 
  pi. 
  iii, 
  fig. 
  10, 
  1889; 
  Proc. 
  U. 
  S. 
  

  

  Nat. 
  Mus., 
  XII, 
  p. 
  281, 
  1889. 
  

   Cardiomya 
  striata 
  Dall, 
  Bull. 
  U. 
  S. 
  Nat. 
  Mus., 
  No. 
  37, 
  pi. 
  LXV, 
  fig. 
  129, 
  1889. 
  

   Not 
  Cardiomya 
  costellata 
  (Deshayes) 
  var. 
  curta 
  Dall, 
  Bull. 
  Mus. 
  Comp. 
  Zool., 
  

  

  XII, 
  p. 
  297, 
  1886. 
  

   Necera 
  multicostata 
  var. 
  curta 
  Verrill, 
  Trans. 
  Conn. 
  Acad., 
  V, 
  p. 
  560, 
  1882. 
  

  

  This 
  comparatively 
  rare 
  species 
  was 
  found 
  at 
  but 
  eight 
  stations 
  o£F 
  

   Marthas 
  Vineyard, 
  in 
  85 
  to 
  158 
  fathoms, 
  1880-1882. 
  

  

  Although 
  this 
  species 
  resembles 
  Cardiomya 
  striata 
  (Jeffreys) 
  in 
  the 
  

   character 
  of 
  its 
  sculpture, 
  the 
  marked 
  difference 
  in 
  outline, 
  especially 
  

   in 
  its 
  clearly 
  defined 
  rostrum, 
  render 
  it 
  advisable 
  to 
  keep 
  the 
  two 
  forms 
  

   separate 
  until 
  a 
  careful 
  comparison 
  of 
  the 
  hinges 
  can 
  satisfactorily 
  

   decide 
  the 
  question 
  of 
  their 
  identity. 
  

  

  The 
  two 
  valves 
  designated 
  as 
  variety 
  eurta 
  have 
  the 
  radiating 
  ribs 
  

   rounded 
  and 
  not 
  angular, 
  but 
  fewer 
  in 
  number 
  than 
  the 
  typical 
  form, 
  

   and 
  must 
  be 
  distinct 
  from 
  cnrta 
  of 
  Jeffreys, 
  which 
  Mr. 
  Dall 
  makes 
  a 
  

   variety 
  of 
  costellata 
  of 
  Deshayes. 
  

  

  