﻿NO. 
  1139. 
  DEEP-WATEB 
  MOLLUSCA—VEBRILL 
  AND 
  BUSH. 
  785 
  

  

  CRYPTODON 
  GRANDIS 
  Verrill. 
  

  

  Cryptodon 
  grandis 
  Verrill, 
  Trans. 
  Codu. 
  Acad., 
  VI, 
  p. 
  436, 
  pi. 
  xliv, 
  5^.22, 
  1885; 
  

   Expl. 
  Albatross, 
  Report 
  U, 
  S. 
  Com. 
  Fish 
  and 
  Fisheries 
  for 
  1883, 
  p. 
  575, 
  1885. 
  — 
  

   Dall, 
  Bull. 
  U. 
  S. 
  Nat. 
  Mus., 
  No. 
  37, 
  p. 
  50, 
  pi. 
  xlvi, 
  fig. 
  22, 
  1889. 
  

  

  Schizotliccrus 
  grandis 
  {pars) 
  Locard, 
  Campagne 
  du 
  " 
  Caudan," 
  Aunales 
  de 
  I'Uni- 
  

   versite 
  de 
  Lyon, 
  p. 
  180, 
  1896. 
  

  

  Tbis 
  large 
  and 
  interesting 
  species, 
  described 
  in 
  detail 
  and 
  well 
  fig- 
  

   ured 
  in 
  the 
  first 
  article 
  quoted 
  above, 
  is 
  a 
  true 
  Cryptodon, 
  although 
  

   very 
  distinct 
  from 
  any 
  of 
  our 
  other 
  species. 
  Therefore 
  it 
  seems 
  strange 
  

   that 
  M. 
  Locard 
  has 
  referred 
  it 
  to 
  the 
  very 
  different 
  genus, 
  Schizothcvrus 
  

   of 
  Conrad, 
  which 
  belongs 
  to 
  the 
  Mactridae. 
  He 
  identifies 
  without 
  ques- 
  

   tion 
  a 
  single 
  valve, 
  dredged 
  by 
  the 
  Caudan 
  off 
  the 
  coast 
  of 
  France, 
  in 
  

   1,710 
  meters, 
  as 
  our 
  species. 
  It 
  is, 
  therefore, 
  doubtful 
  whether 
  his 
  speci- 
  

   men 
  is 
  congeneric 
  with 
  ours, 
  for 
  the 
  latter 
  certainly 
  has 
  no 
  affinity 
  with 
  

   ScJiizotlKcrus. 
  

  

  One 
  live 
  specimen 
  and 
  a 
  few 
  separate 
  valves 
  were 
  dredged 
  at 
  three 
  

   stations 
  between 
  N. 
  lat. 
  38o 
  29', 
  W. 
  long. 
  73° 
  9', 
  and 
  N. 
  lat. 
  35° 
  9' 
  50", 
  

   W. 
  long. 
  740 
  57' 
  40", 
  in 
  938 
  to 
  1,582 
  fathoms, 
  1883-84. 
  

  

  CRYPTODON 
  INSIGNIS, 
  new 
  species. 
  

   (Plate 
  XCI, 
  figs. 
  1,2.) 
  

  

  Cryptodon 
  s«rsw 
  Verrill, 
  Proc. 
  U.S. 
  Nat. 
  Mus., 
  Ill, 
  p. 
  399, 
  1880; 
  Trans. 
  Conn. 
  

   Acad., 
  V, 
  p. 
  .570, 
  1882. 
  

  

  Shell 
  unusually 
  large 
  and 
  thick 
  for 
  the 
  genus, 
  opaque 
  white 
  or 
  

   tinged 
  faintly 
  with 
  reddish 
  internally. 
  Outline 
  soQiewhat 
  variable, 
  

   usually 
  broad-ovate 
  or 
  subquadrate, 
  usually 
  moderately 
  swollen, 
  some- 
  

   times 
  rather 
  compressed. 
  Umbos 
  moderately 
  large, 
  not 
  very 
  promi- 
  

   nent; 
  beaks 
  small 
  and 
  turned 
  forward. 
  Lunule 
  cordate, 
  rather 
  large, 
  

   pretty 
  well 
  defined. 
  The 
  radial 
  folds 
  and 
  lobes 
  are 
  less 
  marked 
  than 
  

   is 
  usual 
  in 
  this 
  genus. 
  A 
  well-marked 
  fold 
  or 
  shallow 
  undulation 
  

   extends 
  from 
  the 
  beak 
  to 
  the 
  posterior 
  margin, 
  opposite 
  the 
  scar 
  of 
  the 
  

   adductor 
  muscle; 
  anterior 
  to 
  this 
  there 
  is 
  abroad, 
  slightly 
  raised 
  ridge, 
  

   extending 
  from 
  the 
  umbo 
  to 
  the 
  siphonal 
  lobe 
  of 
  the 
  margin; 
  in 
  front 
  

   of 
  this 
  there 
  is 
  usually 
  a 
  broad 
  faint 
  depression 
  of 
  the 
  surface 
  which 
  is 
  

   scarcely 
  apparent 
  in 
  many 
  specimens; 
  a 
  posterior 
  groove 
  runs 
  close 
  to 
  

   and 
  nearly 
  parallel 
  with 
  the 
  postero-dorsal 
  margin. 
  The 
  antero-dorsal 
  

   margin, 
  in 
  tlie 
  lunular 
  region, 
  is 
  straight 
  or 
  slightly 
  incurved; 
  the 
  

   anterior 
  end 
  is 
  short, 
  a 
  little 
  prominent 
  below 
  the 
  lunule, 
  and 
  obtusely 
  

   rounded; 
  the 
  ventral 
  margin, 
  is 
  very 
  broadly 
  rounded, 
  usually 
  with 
  a 
  

   slightly 
  more 
  prominent 
  lobe 
  at 
  or 
  just 
  behind 
  the 
  middle, 
  with 
  a 
  more 
  

   decided 
  but 
  obtuse 
  projection 
  (siphonal 
  lobe) 
  farther 
  back 
  where 
  it 
  joins 
  

   the 
  posterior 
  margin, 
  which 
  is 
  usually 
  somewhat 
  incurved, 
  correspond- 
  

   ing 
  to 
  the 
  external 
  wave-like 
  depression, 
  becoming 
  convex 
  opposite 
  the 
  

   posterior 
  external 
  fold; 
  the 
  postero-dorsal 
  margin 
  slopes 
  rapidly 
  from 
  

   the 
  beak 
  and 
  is 
  sometimes 
  broadly 
  rounded, 
  and 
  at 
  others 
  slightly 
  con- 
  

   vex. 
  The 
  surface 
  is 
  covered 
  with 
  conspicuous, 
  more 
  or 
  less 
  irregular, 
  

   Proc. 
  N. 
  M. 
  vol. 
  XX 
  50 
  

  

  