﻿NO. 
  1139. 
  DEEP-WATER 
  MOLLUSCA—VERBILL 
  AND 
  BUSH. 
  867 
  

  

  Our 
  specimens, 
  which 
  are 
  worn 
  and 
  imperfect, 
  referred 
  to 
  this 
  north- 
  

   ern 
  si)ecies, 
  differ 
  somewhat 
  from 
  the 
  typical 
  specimens 
  from 
  Spitz- 
  

   bergen, 
  received 
  from 
  Doctor 
  Friele. 
  They 
  are 
  relatively 
  shorter, 
  

   higher, 
  and 
  somewhat 
  less 
  swollen, 
  with 
  a 
  thicker 
  and 
  heavier 
  shell. 
  

   The 
  posterior 
  end 
  is 
  less 
  produced 
  and 
  less 
  tapered, 
  so 
  that 
  it 
  has 
  a 
  

   more 
  ovate 
  form. 
  The 
  hinge- 
  teeth 
  are 
  stouter; 
  the 
  posterior 
  series 
  is 
  

   shorter 
  but 
  contains 
  the 
  same 
  number 
  of 
  teeth 
  in 
  specimens 
  of 
  simihir 
  

   size. 
  With 
  the 
  amount 
  of 
  material 
  that 
  we 
  have 
  for 
  examination, 
  the 
  

   differences, 
  however, 
  seem 
  hardly 
  sufficient 
  to 
  warrant 
  the 
  separation 
  

   of 
  our 
  shells 
  as 
  a 
  distinct 
  species. 
  We 
  therefore 
  propose 
  the 
  varietal 
  

   name 
  amblia 
  for 
  our 
  specimens. 
  

  

  A 
  few 
  separate 
  valves, 
  at 
  two 
  stations, 
  north 
  of 
  Cape 
  Cod, 
  in 
  110 
  to 
  

   122 
  fathoms, 
  1878-79. 
  

  

  YOLDIELLA 
  FRATERNA, 
  new 
  species. 
  

   (Flutes 
  LXXX, 
  fig. 
  5; 
  LXXXII, 
  tig. 
  8.) 
  

  

  Yoldia 
  frigida 
  Verrill, 
  Traus. 
  Conn. 
  Acad., 
  VI, 
  p. 
  279, 
  1884; 
  Expl. 
  Albatross, 
  

   Eeport 
  U. 
  S. 
  Cora. 
  Fish 
  and 
  Fisheries 
  for 
  1883, 
  p. 
  576, 
  1885 
  (iupart). 
  

  

  Shell 
  small, 
  thin, 
  delicate, 
  irregularly 
  elliptical 
  in 
  form, 
  the 
  posterior 
  

   end 
  being 
  a 
  little 
  the 
  longer, 
  unusually 
  broad, 
  and 
  slightly 
  produced 
  

   above, 
  but 
  not 
  distinctly 
  angulated, 
  with 
  a 
  glossy, 
  iridescent, 
  yellow- 
  

   ish 
  green 
  epidermis. 
  Umbos 
  a 
  little 
  swollen 
  ; 
  the 
  beaks 
  small, 
  scarcely 
  

   l^rominent, 
  and 
  subcentral. 
  The 
  anterior 
  end 
  is 
  broad, 
  a 
  little 
  produced 
  

   in 
  the 
  middle, 
  and 
  obtusely 
  rounded; 
  the 
  dorsal 
  margin 
  is 
  nearly 
  

   horizontal 
  in 
  the 
  region 
  of 
  the 
  teeth; 
  distally, 
  sharp, 
  and 
  convex, 
  then 
  

   sloping 
  rapidly 
  to 
  the 
  middle 
  of 
  the 
  anterior 
  end. 
  The 
  ventral 
  margin 
  

   is 
  broadly 
  rounded, 
  expanding 
  a 
  little 
  posteriorly 
  and 
  then 
  ascending 
  

   pretty 
  rapidly 
  to 
  the 
  posterior 
  tip 
  which 
  is 
  obtusely 
  rounded 
  sai)eri- 
  

   orly; 
  postero-dorsal 
  margin 
  slightly 
  convex 
  and 
  nearly 
  horizontal 
  for 
  

   the 
  greater 
  part 
  of 
  its 
  length. 
  The 
  surface 
  beneath 
  the 
  epidermis 
  is 
  

   marked 
  only 
  by 
  faint 
  lines 
  of 
  growth. 
  The 
  hinge-margin 
  is 
  thin, 
  

   rather 
  delicate, 
  with 
  the 
  two 
  series 
  of 
  teeth 
  of 
  nearly 
  equal 
  length 
  and 
  

   diverging 
  from 
  the 
  beaks 
  at 
  a 
  broad 
  angle; 
  each 
  series 
  contains 
  about 
  

   ten 
  rather 
  thin 
  and 
  delicate 
  teeth, 
  of 
  which 
  the 
  one 
  or 
  two 
  proximal 
  

   ones 
  are 
  very 
  small 
  and 
  rather 
  indistinct. 
  Beneath 
  tlie 
  beak 
  the 
  

   margin 
  is 
  attenuated 
  and 
  interrupted 
  by 
  a 
  small, 
  oblong 
  resilium 
  which 
  

   occupies 
  the 
  entire 
  thickness 
  of 
  the 
  margin 
  and 
  a 
  slight 
  notch 
  in 
  the 
  

   beak. 
  The 
  pallial 
  sinus 
  is 
  relatively 
  rather 
  large 
  and 
  deep, 
  but 
  in 
  

   most 
  sijecimens 
  is 
  invisible. 
  

  

  Length 
  of 
  the 
  figured 
  specimen, 
  4 
  mm.; 
  height, 
  about 
  2^ 
  mm. 
  

  

  A 
  comparatively 
  small 
  number 
  of 
  specimens, 
  at 
  about 
  twenty 
  sta- 
  

   tions, 
  between 
  N. 
  lat. 
  47° 
  40', 
  W. 
  long. 
  47° 
  35' 
  30", 
  and 
  N. 
  lat. 
  37° 
  8', 
  

   W. 
  long. 
  740 
  33', 
  in 
  90 
  to 
  1,608 
  fathoms, 
  1873-1886. 
  

  

  This 
  is 
  a 
  deep-water 
  form 
  formerly 
  identified 
  by 
  us 
  as 
  Yoldia 
  frigida 
  

   Torell. 
  

  

  