﻿802 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM. 
  vol.xx. 
  

  

  rather 
  elongated, 
  lateral 
  tooth 
  ; 
  the 
  left 
  valve 
  also 
  has 
  a 
  small, 
  elongated, 
  

   tooth-like 
  expansion 
  posterior 
  to 
  the 
  cartilage 
  plate. 
  

  

  Length, 
  4.5 
  mm.; 
  height, 
  2.25 
  mm.; 
  breadth, 
  1.5 
  mm. 
  

  

  This 
  species 
  may 
  easily 
  be 
  mistaken 
  for 
  the 
  young 
  of 
  G. 
  ohcsa 
  and 
  G. 
  

   fraterna; 
  the 
  structure 
  of 
  the 
  hinge 
  is, 
  however, 
  characteristic. 
  

  

  A 
  comparatively 
  few 
  specimens, 
  at 
  seven 
  station, 
  between 
  X. 
  hit. 
  

   4]o 
  28' 
  30", 
  W. 
  long. 
  65° 
  35' 
  30", 
  and 
  35^ 
  49' 
  30", 
  W. 
  long. 
  74° 
  34' 
  45", 
  

   in 
  515 
  to 
  1,290 
  fathoms, 
  1883-1886. 
  

  

  CUSPIDARIA 
  VENTRICOSA, 
  new 
  species. 
  

   (Plates 
  LXXII, 
  fig. 
  5; 
  LXXVI, 
  fig. 
  6.) 
  

  

  Shell 
  large, 
  rather 
  solid, 
  swollen, 
  with 
  a 
  ventral 
  enlargement 
  and 
  a 
  

   moderately 
  elongated, 
  tapered 
  rostrum. 
  Umbos 
  swollen 
  and 
  i)romi- 
  

   nent; 
  beaks 
  incurved. 
  Antero-dorsal 
  margin 
  at 
  first 
  nearly 
  straight, 
  

   then 
  broadly 
  rounded 
  with 
  the 
  extreme 
  anterior 
  end 
  a 
  little 
  prominent; 
  

   ventral 
  margin 
  decidedly 
  excurved 
  in 
  the 
  middle, 
  corresponding 
  to 
  the 
  

   exterior 
  swelling; 
  at 
  the 
  base 
  of 
  the 
  rostrum 
  slightly 
  concave 
  ; 
  postero- 
  

   dorsal 
  margin 
  somewhat 
  concave, 
  the 
  most 
  so 
  at 
  the 
  base 
  of 
  the 
  ros- 
  

   trum, 
  which 
  is 
  obtusely 
  rounded 
  at 
  the 
  end. 
  Exterior 
  covered 
  with 
  very 
  

   distinct 
  lines 
  of 
  growth 
  and 
  irregular, 
  stronger, 
  concentric 
  grooves. 
  

   C"^ 
  the 
  rostrum 
  there 
  is 
  an 
  obtuse, 
  diagonal 
  ridge 
  running 
  to 
  the 
  ven- 
  

   tral 
  angle 
  of 
  the 
  tip; 
  between 
  this 
  and 
  the 
  dorsal 
  margin 
  there 
  are 
  two 
  

   others 
  less 
  distinct. 
  The 
  anterior 
  hinge-margin 
  is 
  decidedly 
  thickened 
  

   in 
  both 
  valves 
  and 
  projects 
  inward 
  with 
  a 
  thick, 
  rounded 
  edge, 
  most 
  

   conspicuous 
  iu 
  the 
  right 
  valve, 
  in 
  which 
  it 
  is 
  abruptly 
  much 
  narrowed 
  

   near 
  the 
  cartilage-plate; 
  in 
  this 
  valve 
  the 
  lateral 
  tooth 
  is 
  short, 
  stout, 
  

   obtuse, 
  very 
  prominent, 
  and 
  situated 
  close 
  to 
  the 
  beak, 
  its 
  length 
  along 
  

   the 
  margin 
  not 
  much 
  exceeding 
  its 
  height; 
  cartilage-plate 
  small, 
  rela- 
  

   tively 
  wide, 
  oblique, 
  directed 
  backward 
  and 
  downward, 
  and 
  closely 
  

   united 
  to 
  the 
  lateral 
  tooth, 
  there 
  being 
  only 
  a 
  slight, 
  rounded 
  notch 
  

   between. 
  

  

  Length 
  of 
  the 
  larger 
  specimen, 
  30 
  mm.; 
  height, 
  29 
  mm.; 
  breadth, 
  18 
  

   mm.; 
  beak 
  to 
  end 
  of 
  rostrum, 
  16 
  mm.; 
  beak 
  to 
  anterior 
  end, 
  17 
  mm. 
  

   Another 
  specimen 
  is 
  25 
  mm. 
  long; 
  17 
  mm. 
  high; 
  12 
  mm. 
  broad. 
  

  

  Four 
  valves, 
  at 
  three 
  station, 
  between 
  N. 
  lat. 
  40° 
  29', 
  W. 
  long. 
  6Q° 
  4', 
  

   and 
  N. 
  lat. 
  38° 
  27' 
  30", 
  W. 
  long. 
  70^54' 
  30", 
  in 
  349 
  to 
  1,769 
  fathoms, 
  

   1882-1886. 
  

  

  This 
  species 
  has 
  some 
  resemblance 
  to 
  C. 
  glacialis, 
  but 
  is 
  a 
  stouter 
  and 
  

   more 
  swollen 
  shell, 
  with 
  a 
  relatively 
  larger 
  rostrum, 
  much 
  more 
  elon- 
  

   gated 
  and 
  less 
  prominent 
  lateral 
  tooth, 
  and 
  A^ery 
  different 
  cartilage- 
  

   plate. 
  The 
  latter 
  does 
  not 
  have 
  the 
  swollen 
  ventral 
  region, 
  character- 
  

   istic 
  of 
  our 
  species, 
  nor 
  the 
  diagonal 
  ribs 
  on 
  the 
  rostrum. 
  

  

  