﻿840 
  PBOCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM. 
  

  

  closely 
  crowded, 
  often 
  even 
  in 
  contact 
  in 
  the 
  radial 
  rows, 
  and 
  in 
  

   form 
  either 
  ronnded 
  or 
  elliptical 
  with 
  the 
  longest 
  diameter 
  in 
  the 
  

   direction 
  of 
  the 
  concentric 
  lines, 
  with 
  the 
  snmmit 
  evenly 
  ronnded, 
  

   showing" 
  no 
  tendency 
  to 
  the 
  subconical 
  or 
  mncronate 
  form. 
  When 
  

   perfect 
  they 
  resemble 
  small 
  blisters 
  with 
  the 
  surface 
  roughened 
  or 
  

   minutely 
  grauulose 
  under 
  the 
  microscope; 
  when 
  broken 
  or 
  worn 
  off", 
  as 
  

   frequently 
  happens, 
  the 
  basal 
  part 
  remains 
  in 
  the 
  form 
  of 
  a 
  semicircular 
  

   or 
  semieliiptical, 
  imbricated, 
  arched 
  scale, 
  usually 
  considerably 
  ele- 
  

   vated 
  above 
  the 
  surface 
  and 
  connected 
  by 
  very 
  delicate 
  concentric 
  

   raised 
  lines. 
  The 
  surface 
  of 
  the 
  anterior 
  auricle 
  of 
  the 
  left 
  valve 
  is 
  

   roughened 
  by 
  close, 
  elevated, 
  concentric 
  lines, 
  and 
  from 
  four 
  to 
  six 
  

   well-marked 
  radiating 
  ridges 
  or 
  ribs, 
  upon 
  which 
  the 
  concentric 
  lines 
  

   form 
  regular 
  elevated 
  arched 
  projections, 
  often 
  so 
  crowded 
  as 
  to 
  be 
  

   imbricated; 
  in 
  some 
  young 
  examples, 
  like 
  the 
  one 
  figured, 
  the 
  concen- 
  

   tric 
  lines 
  on 
  the 
  auricle 
  are 
  less 
  crowded 
  and 
  only 
  two 
  or 
  tliree 
  of 
  the 
  

   radial 
  ribs 
  are 
  developed; 
  in 
  such 
  examples 
  the 
  vesicles 
  on 
  the 
  body 
  

   of 
  the 
  shell 
  are 
  relatively 
  fewer, 
  larger, 
  more 
  rounded, 
  and 
  much 
  less 
  

   crowded 
  in 
  tlie 
  radial 
  series, 
  in 
  some 
  specimens 
  the 
  j^osterior 
  margin, 
  

   below 
  the 
  auricle, 
  is 
  nearly 
  smooth 
  or 
  marked 
  only 
  by 
  the 
  fine 
  lines 
  of 
  

   growth, 
  while 
  in 
  others, 
  esi)ecially 
  larger 
  sjiecimens, 
  this 
  region 
  is 
  cov- 
  

   ered 
  by 
  rather 
  sharp 
  granules, 
  some 
  of 
  which, 
  toward 
  the 
  ventral 
  

   margin, 
  change 
  to 
  pointed 
  scales 
  arranged 
  in 
  crowded 
  radial 
  rows. 
  

   The 
  raised 
  concentric 
  lines 
  on 
  the 
  right 
  valve 
  are 
  generally 
  more 
  or 
  

   less 
  appressed 
  and 
  sometimes 
  imbricated; 
  toward 
  the 
  ventral 
  margin 
  

   some 
  of 
  them 
  show 
  very 
  fine 
  microscopic 
  crenulations, 
  which 
  are 
  much 
  

   less 
  distinct 
  than 
  on 
  C. 
  imbri/er, 
  as 
  figured 
  by 
  Sars. 
  

  

  This 
  species 
  is 
  distinct 
  from 
  that 
  figured 
  by 
  Mr. 
  Dall' 
  under 
  the 
  

   name 
  of 
  C. 
  imhrifer. 
  Llis 
  specimen 
  apparently 
  belongs 
  to 
  the 
  follow- 
  

   ing 
  species. 
  

  

  Several 
  live 
  and 
  dead 
  specimens, 
  at 
  eleven 
  stations 
  between 
  N. 
  lat. 
  

   440 
  34/^ 
  w. 
  long. 
  56° 
  41' 
  45", 
  and 
  K 
  lat. 
  39° 
  48' 
  30", 
  AV. 
  long. 
  70° 
  54', 
  

   in 
  99i 
  to 
  547 
  fathoms, 
  1872-1885. 
  

  

  CYCLOPECTEN 
  SUBIMBRIFER 
  Verrill 
  and 
  Bush. 
  

   (Plate 
  LXXXV, 
  ligs. 
  8, 
  9.) 
  

  

  I'eclcn 
  hoskyiisi 
  Vkruili., 
  Trans. 
  Conu. 
  Acad., 
  V, 
  p. 
  581, 
  i>l. 
  xliv, 
  iig. 
  11, 
  1882. 
  Not 
  

  

  Forbes. 
  

   I'ecteii 
  {Pseudamnsium) 
  imhrifer 
  Dall, 
  Bull. 
  Mns. 
  Conip. 
  Zool., 
  XII, 
  p. 
  220 
  (iu 
  

  

  part), 
  pi. 
  IV, 
  figs. 
  4«, 
  ih, 
  1886; 
  Bull. 
  U. 
  S. 
  Nat. 
  Mus., 
  No. 
  37, 
  p. 
  34 
  (iu 
  part), 
  pi. 
  

  

  IV, 
  tigs. 
  4a., 
  4fc, 
  1889. 
  

   Cyclopecten 
  sithimhrifrr 
  Merrill 
  and 
  Busii, 
  in 
  Verrill, 
  Trans. 
  Conu. 
  Acad., 
  X, 
  

  

  pp. 
  84, 
  92, 
  1897, 
  

  

  Shell 
  small, 
  inequivalved, 
  white 
  or 
  grayish 
  white, 
  translucent, 
  length 
  

   and 
  height 
  nearly 
  equal. 
  Dorsal 
  margin 
  straight. 
  Anterior 
  auricle 
  in 
  

   the 
  left 
  valve 
  rather 
  large 
  and 
  broad, 
  the 
  outer 
  end 
  obtusely 
  rounded, 
  

  

  Blake 
  Mollusca, 
  jil. 
  i\ 
  , 
  tigs, 
  4a, 
  -ih. 
  

  

  