﻿NO. 
  1139. 
  DEE 
  P-WATEB 
  MOLLUSC 
  A— 
  VEBRILL 
  AND 
  BUSH. 
  855 
  

  

  LEDA 
  PERNULA 
  (Muller). 
  

  

  (Plate 
  LXXXII, 
  fig. 
  2.) 
  

  

  Leda 
  pernula 
  G. 
  O. 
  Sars, 
  Mollusca 
  Reg. 
  ArcticsB 
  Norvegife, 
  p. 
  35, 
  pi. 
  5, 
  figs. 
  1 
  

   a-d, 
  1878. 
  — 
  Jeffreys, 
  Proc. 
  Zool. 
  Soc, 
  Londou, 
  p. 
  574, 
  June, 
  1879. 
  — 
  ^'er- 
  

   RiLL, 
  Proc. 
  U. 
  S. 
  Nat. 
  Mus., 
  Ill, 
  p. 
  401, 
  1881; 
  Trans. 
  Conn. 
  Acad., 
  V, 
  p. 
  572, 
  

   1882; 
  not 
  VI, 
  p. 
  280, 
  pi. 
  xxx, 
  figs. 
  14, 
  14a, 
  1884.— 
  Not 
  Dall, 
  Bull. 
  U. 
  S. 
  Nat. 
  

   Mus., 
  No. 
  37, 
  pi. 
  XLV, 
  figs. 
  14, 
  14a, 
  1889. 
  

  

  Found 
  at 
  a 
  number 
  of 
  stations 
  between 
  K. 
  lat. 
  46^1 
  23', 
  W. 
  long. 
  52° 
  45', 
  

   and 
  N. 
  lat. 
  37° 
  8', 
  W. 
  long. 
  74° 
  33', 
  in 
  25 
  to 
  471 
  fathoms, 
  1872-1885. 
  

  

  LEDA 
  CAUDATA 
  (Donovan). 
  

   (Plate 
  LXXXII, 
  fig. 
  1.) 
  

  

  Area 
  caudata 
  Donovan, 
  British 
  Shells, 
  pi. 
  lxxviii; 
  Chenu 
  ed., 
  p. 
  50, 
  pi. 
  xvii, 
  

  

  figs. 
  8-12. 
  

   Leda 
  caudata 
  LovloN, 
  Ind. 
  Moll. 
  Scand., 
  p. 
  34. 
  — 
  Gould, 
  Rep. 
  on 
  Invert, 
  of 
  Mass., 
  

  

  Binney's 
  ed., 
  p. 
  165, 
  fig. 
  471, 
  1870. 
  — 
  Tryon, 
  Aiuer. 
  Mar. 
  Conch., 
  p. 
  182, 
  pi. 
  

  

  xxxviii, 
  figs. 
  494, 
  495, 
  1873. 
  

   Leda 
  pernula 
  Verrill, 
  Trans. 
  Conn. 
  Acad., 
  V, 
  p. 
  572, 
  1882, 
  in 
  part; 
  VI, 
  p. 
  280, 
  

  

  pi. 
  XXX, 
  figs. 
  14, 
  14a, 
  1884.— 
  Dall, 
  Bull. 
  U. 
  S. 
  Nat. 
  Mus., 
  No. 
  S7, 
  pi. 
  xlv, 
  

  

  figs. 
  14, 
  14tt, 
  1889.— 
  ( 
  ? 
  ) 
  Bush, 
  Bull. 
  Mus. 
  Comp. 
  Zool., 
  XXIII, 
  p. 
  234, 
  1893. 
  

   Leda 
  caudata 
  Verrill 
  and 
  Bush, 
  Anier. 
  Journ. 
  Sci., 
  Ill, 
  p. 
  54, 
  fig. 
  19, 
  January, 
  

  

  1897. 
  

  

  This 
  deeper- 
  water 
  form, 
  i)reviously 
  identified 
  as 
  Leda 
  pernula, 
  was 
  

   found 
  at 
  a 
  very 
  few 
  stations 
  between 
  IST. 
  lat. 
  42° 
  57', 
  W. 
  long. 
  69° 
  50', 
  and 
  

   N. 
  lat. 
  37° 
  16' 
  30", 
  W. 
  long. 
  74° 
  20' 
  36", 
  in 
  102 
  to 
  641 
  fathoms, 
  1874-1885. 
  

  

  LEDELLA 
  Verrill 
  and 
  Bush, 
  1897. 
  

  

  Junonia 
  Seguenza, 
  Nuculidi 
  terziarie 
  merid. 
  d' 
  Ital., 
  R. 
  Acad. 
  Lincei, 
  p. 
  1175, 
  

  

  1877 
  (notof 
  HiJBNER). 
  

   Ledella 
  Verrill 
  and 
  Bush, 
  Amer. 
  Journ. 
  Sci., 
  Ill, 
  pp. 
  54, 
  62, 
  January, 
  1897. 
  

  

  Type. 
  — 
  Ledella 
  messanensis 
  (Seguenza). 
  

  

  This 
  group 
  includes 
  a 
  large 
  number 
  of 
  small 
  species, 
  both 
  living 
  and 
  

   fossil, 
  in 
  which 
  the 
  shell 
  is 
  rather 
  short, 
  usually 
  ovate 
  or 
  swollen, 
  with 
  a 
  

   small, 
  acute 
  or 
  subacute 
  uuicariate 
  rostrum, 
  situated 
  medially 
  or 
  sub- 
  

   medially, 
  and 
  defined 
  below 
  by 
  an 
  emargination 
  or 
  undulation 
  in 
  the 
  

   postero-ventral 
  margin. 
  The 
  postero-dorsal 
  margin 
  is 
  convex. 
  The 
  

   escutcheon 
  or 
  ligamental 
  area 
  is 
  very 
  distinctly 
  defined 
  by 
  the 
  carina, 
  

   but 
  is 
  not 
  sunken. 
  The 
  chondrophore 
  is 
  usually 
  small 
  but 
  distinct. 
  The 
  

   siphon 
  tubes 
  are 
  separate, 
  at 
  least 
  in 
  some 
  species. 
  It 
  includes 
  numerous 
  

   minute 
  tertiary 
  species 
  referred 
  by 
  Seguenza 
  to 
  the 
  section 
  of 
  Leda 
  

   named 
  by 
  him 
  Junonia, 
  and 
  also 
  a 
  considerable 
  number 
  of 
  recent 
  deep- 
  

   water 
  species 
  generally 
  described 
  by 
  authors 
  under 
  Leda. 
  As 
  the 
  

   name 
  Junonia 
  was 
  i^reoccupied, 
  the 
  group, 
  which 
  seemed 
  to 
  be 
  of 
  generic 
  

   value, 
  required 
  a 
  new 
  name. 
  

  

  The 
  following 
  species 
  appear 
  to 
  belong 
  here: 
  

  

  L. 
  seminula 
  (Seguenza), 
  L. 
  nicotrce 
  (Seguenza), 
  X. 
  peraffinis 
  (Se- 
  

  

  