﻿856 
  PROCEEDIJSFGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM. 
  

  

  guenza), 
  L. 
  rectidorsata 
  (Segiienza), 
  L. 
  confusa 
  (Seguenza), 
  fossil; 
  L. 
  

   soUdula 
  (Smitli) 
  and 
  L. 
  semen 
  (Smith), 
  from 
  off 
  Brazil; 
  L. 
  confinis 
  

   (Smith), 
  oft" 
  the 
  Azores; 
  L. 
  inopinata 
  (Smith), 
  L. 
  prolata 
  (Smith), 
  and 
  

   L. 
  ultima 
  (Smith), 
  from 
  the 
  Pacific; 
  L. 
  mensanensis 
  (Seguenza), 
  from 
  

   oft" 
  the 
  Barbados, 
  northward; 
  L. 
  wessanensis 
  (Seguenza) 
  var. 
  sw&/er/,v 
  

   Verrill 
  and 
  Bush, 
  oft" 
  Dehi 
  ware 
  Bay, 
  northward; 
  and 
  X. 
  ^art'a 
  Yerrill 
  

   and 
  Bush, 
  oft" 
  Marthas 
  Vineyard. 
  

  

  LEDELLA 
  MESSANENSIS 
  (Seguenza). 
  

   (Plate 
  LXXXI, 
  fig. 
  9.) 
  

  

  Leda 
  acuminata 
  Jeffreys, 
  Aim. 
  Mag. 
  Nat. 
  Hist., 
  p. 
  69, 
  .July, 
  1870 
  (not 
  VoN 
  

   Buch). 
  — 
  Seguenza, 
  Nnculidi 
  terziarie 
  mericl. 
  d'ltal., 
  K. 
  Acad. 
  Lincei, 
  1877, 
  

   p. 
  1175, 
  pi. 
  Ill, 
  figs. 
  15, 
  15a, 
  15e. 
  

  

  Leda 
  mesaanensis 
  Jeefreys, 
  Proc. 
  Zool. 
  Soc. 
  London, 
  p. 
  576, 
  June, 
  1879. 
  — 
  Smith, 
  

   E. 
  A., 
  Eeport 
  Voy. 
  Challenger, 
  Zool. 
  Lamellibranchiata, 
  XIII, 
  p. 
  237, 
  1885. 
  — 
  

   Dall, 
  Bull. 
  Mus. 
  Comp. 
  Zool., 
  XII, 
  p. 
  249, 
  1886; 
  Bull. 
  U. 
  S. 
  Nat. 
  Mus., 
  No, 
  

   37, 
  p. 
  44, 
  1889. 
  

  

  The 
  shell 
  which 
  is 
  here 
  regarded 
  as 
  the 
  true 
  messanensis 
  is 
  small, 
  

   swollen, 
  ovate, 
  nearly 
  equilateral, 
  with 
  a 
  distinct, 
  short, 
  oblique 
  rostrum 
  

   bent 
  downward 
  at 
  the 
  tip 
  and 
  sex)arated 
  from 
  the 
  body 
  of 
  the 
  shell 
  by 
  

   a 
  distinct 
  depression 
  and 
  marginal 
  indentation. 
  The 
  shell 
  is 
  tliick 
  and 
  

   solid 
  for 
  so 
  small 
  a 
  species; 
  its 
  surface 
  is 
  covered 
  with 
  fine, 
  regular, 
  

   raised, 
  thin, 
  concentric 
  lines 
  separated 
  by 
  wider 
  concave 
  grooves. 
  The 
  

   hinge-margin 
  is 
  thick, 
  strong, 
  with 
  about 
  seven 
  or 
  eight, 
  mostly 
  strong, 
  

   nearly 
  erect, 
  and 
  not 
  crowded, 
  teeth 
  in 
  each 
  series. 
  The 
  choudrophore 
  

   is 
  relatively 
  large, 
  triangular, 
  and 
  projects 
  on 
  the 
  inner 
  margin. 
  The 
  

   epidermis 
  is 
  pale 
  yellow. 
  According 
  to 
  Jeffreys 
  the 
  siphon 
  tubes 
  are 
  

   long 
  and 
  separate. 
  

  

  Length, 
  about 
  2.G 
  mm. 
  ; 
  height, 
  about 
  2 
  mm. 
  

  

  A 
  few 
  specimens, 
  at 
  three 
  stations 
  between 
  K. 
  lat. 
  38° 
  29', 
  W. 
  long. 
  

   73° 
  9', 
  and 
  N. 
  lat. 
  37°, 
  W. 
  long. 
  71° 
  54', 
  in 
  965 
  to 
  2,620 
  fathoms, 
  1884-85. 
  

   South 
  to 
  the 
  Barbados, 
  in 
  32 
  to 
  2,033 
  fathoms.— 
  Dall. 
  

  

  LEDELLA 
  MESSANENSIS 
  (Seguenza) 
  variety 
  SUBLEVIS, 
  new. 
  

   (Plate 
  LXXXI, 
  fig. 
  7.) 
  

  

  Toldia 
  messanensis, 
  variety 
  Verrill, 
  Trans. 
  Conn. 
  Acad., 
  VI, 
  pp. 
  227, 
  280, 
  1884; 
  

  

  Expl. 
  Albatross, 
  Report 
  U. 
  S. 
  Com. 
  Fish 
  and 
  Fisheries 
  for 
  1883, 
  p. 
  576, 
  1885. 
  

   Ledella 
  messanensis, 
  variety 
  Verrill 
  and 
  Bush, 
  Amer. 
  Journ. 
  Sci., 
  Ill, 
  p. 
  60, 
  

  

  fig. 
  13, 
  January, 
  1897. 
  

  

  This 
  variety 
  differs 
  from 
  the 
  form 
  above 
  described, 
  principally 
  in 
  

   having 
  the 
  concentric 
  sculpture 
  wholly 
  or 
  partially 
  obsolete 
  and 
  in 
  its 
  

   somewhat 
  more 
  elongated 
  form. 
  It 
  has 
  nine 
  or 
  ten 
  teeth 
  in 
  each 
  

   series, 
  due 
  perhaps 
  to 
  the 
  larger 
  size 
  of 
  the 
  specimen. 
  

  

  Comparatively 
  few 
  specimens, 
  at 
  thirteen 
  stations, 
  between 
  N. 
  lat. 
  

   400 
  47/^ 
  w. 
  long, 
  61° 
  4', 
  and 
  N. 
  lat. 
  38° 
  20', 
  W. 
  long. 
  70° 
  8' 
  30", 
  in 
  1,188 
  

   to 
  2,033 
  fathoms, 
  1883-1886. 
  

  

  