﻿NO. 
  1139. 
  DEEP-WATER 
  MOLLUSCA—VERRILL 
  AND 
  BUSH. 
  811 
  

  

  margin; 
  external 
  to 
  this 
  there 
  are 
  remnants 
  of 
  a 
  small 
  anterior 
  liga- 
  

   ment 
  occupying 
  a 
  short 
  furrow. 
  Commencing 
  behind 
  the 
  beak 
  and 
  

   extending 
  to 
  the 
  base 
  of 
  the 
  rostrum, 
  there 
  is 
  a 
  conij)aratively 
  large 
  

   and 
  prominent 
  lamelliform 
  process 
  rising 
  from 
  beneath 
  tlie 
  margin 
  and 
  

   projecting 
  downward, 
  with 
  the 
  face 
  portion 
  broadly 
  rounded, 
  and 
  its 
  

   upper 
  surface 
  concave. 
  Above 
  the 
  base 
  of 
  this, 
  and 
  extending 
  from 
  

   near 
  the 
  beak 
  to 
  about 
  the 
  middle 
  of 
  the 
  rostnim, 
  is 
  a 
  narrow, 
  slightly 
  

   thickened 
  ridge 
  separated 
  from 
  the 
  dorsal 
  margin 
  by 
  a 
  narrow 
  furrow. 
  

  

  Length, 
  C 
  mm.; 
  height, 
  4.5 
  mm.; 
  breadth, 
  about 
  3 
  mm. 
  

  

  One 
  valve, 
  station 
  2055, 
  among 
  Forauiinifera, 
  X, 
  lat. 
  27° 
  22', 
  W. 
  long. 
  

   78° 
  7' 
  30", 
  in 
  338 
  fathoms, 
  1880. 
  

  

  This 
  species 
  has 
  considerable 
  resemblance 
  to 
  H. 
  claHculata 
  Dall, 
  but 
  

   the 
  hitter 
  is 
  more 
  regularly 
  ovate 
  in 
  form, 
  and 
  has 
  a 
  much 
  shorter 
  and 
  

   broader 
  rostrum, 
  and 
  somewhat 
  coarser 
  sculpture. 
  The 
  posterior 
  

   shelf-like 
  clavicle 
  also 
  differs 
  in 
  form, 
  being 
  quite 
  narrow 
  for 
  a 
  consider- 
  

   able 
  distance 
  next 
  the 
  cartilage-pit, 
  and 
  more 
  expanded 
  distally. 
  The 
  

   shell 
  described 
  and 
  figured 
  by 
  Smith^ 
  under 
  the 
  same 
  name 
  appears 
  to 
  

   be 
  a 
  distinct 
  species, 
  and 
  may 
  be 
  identical 
  with 
  our 
  shell, 
  for 
  it 
  has 
  

   nearly 
  the 
  same 
  form 
  and 
  agrees 
  closely 
  in 
  the 
  narrow 
  tapered 
  rostrum. 
  

   The 
  figure 
  of 
  the 
  interior, 
  however, 
  in 
  that 
  case, 
  is 
  incorrect, 
  owing 
  to 
  

   the 
  omission 
  of 
  the 
  clavicle, 
  and 
  apparently 
  the 
  substitution 
  of 
  the 
  hinge 
  

   of 
  the 
  left 
  valve 
  for 
  the 
  right. 
  

  

  MYONERA 
  GIGANTEA 
  Verrill. 
  

  

  (Plate 
  LXXVI, 
  fig^s. 
  4, 
  5.) 
  

  

  Necera 
  gigantea 
  YERHiLh, 
  Trans. 
  Conu. 
  Acad., 
  VI, 
  pp. 
  223, 
  277, 
  1884; 
  Expl. 
  Alba- 
  

   tross, 
  Report 
  U. 
  S. 
  Com. 
  Fish 
  and 
  Fisheries 
  for 
  1883, 
  p. 
  574, 
  1885. 
  

  

  Three 
  imperfect, 
  dead 
  specimens 
  have 
  been 
  found 
  at 
  three 
  stations 
  

   between 
  N. 
  lat. 
  38° 
  22', 
  W. 
  long. 
  70- 
  17' 
  30", 
  and 
  N. 
  lat. 
  37° 
  56' 
  20", 
  

   W. 
  long. 
  70° 
  57' 
  30", 
  in 
  1,825 
  to 
  1,917 
  fathoms, 
  1883 
  and 
  1886. 
  

  

  MYONERA 
  RUGINOSA 
  (Jeffreys) 
  Verrill 
  and 
  Bush. 
  

  

  (Plates 
  LXXII, 
  fig. 
  4; 
  LXXIV, 
  fig. 
  2.) 
  

  

  Newra 
  ruginosa 
  Jeffreys, 
  Proc. 
  Zoi'd. 
  Soc. 
  London, 
  p. 
  942, 
  pi. 
  lxxi, 
  fig. 
  7, 
  Novem- 
  

   ber, 
  1881. 
  — 
  Smith, 
  E. 
  A., 
  Report 
  Yoy. 
  Challenger, 
  Zool. 
  Lamellibranchiata, 
  

   XIII, 
  p. 
  35, 
  1885. 
  

  

  Shell 
  small, 
  vshort, 
  broad-ovate, 
  not 
  much 
  swollen, 
  with 
  a 
  short, 
  wide, 
  

   gaping, 
  obliquely 
  truncate 
  rostrum. 
  Umbos 
  small, 
  prominent, 
  not 
  much 
  

   swollen; 
  beaks 
  small, 
  prominent, 
  incurved, 
  smooth 
  and 
  shining. 
  The 
  

   anterior 
  portion 
  is 
  evenly 
  rounded, 
  nearly 
  semicircular; 
  the 
  antero- 
  

   dorsal 
  margin 
  is 
  convex 
  and 
  prominent; 
  the 
  ventral 
  margin 
  is 
  broadly 
  

   and 
  evenly 
  rounded, 
  except 
  at 
  the 
  base 
  of 
  the 
  rostrum 
  where 
  it 
  is 
  sin- 
  

   uous 
  and 
  incurved; 
  the 
  postero-dorsal 
  margin 
  is 
  nearly 
  straight 
  to 
  tlie 
  

  

  ' 
  Report 
  Yoy. 
  Challenger 
  Zool. 
  Lami'llibranchiata, 
  XIII, 
  p. 
  52, 
  pi. 
  ix, 
  figs. 
  8-8&, 
  1885. 
  

  

  