﻿NO. 
  1139. 
  DEEP-WATEB 
  MOLLVSCA—VEREILL 
  AND 
  BUSH. 
  857 
  

  

  LEDELLA 
  PARVA 
  Verrill 
  and 
  Bush. 
  

   (Plate 
  LXXXI, 
  tig. 
  1.) 
  

  

  Ledclla 
  parva 
  Yekrill 
  aud 
  Busii, 
  Araer. 
  .louiu. 
  Sci., 
  Ill, 
  p. 
  54, 
  fig. 
  18, 
  January, 
  

   1897. 
  

  

  Shell 
  minute, 
  narrow-ovate, 
  the 
  anterior 
  end 
  the 
  longer 
  and 
  obtusely 
  

   rounded, 
  and 
  the 
  posterior 
  end 
  with 
  a 
  short, 
  subtruncate, 
  median 
  ros- 
  

   trum. 
  Umbos 
  somewhat 
  swollen; 
  beaks 
  a 
  little 
  prominent 
  and 
  turned 
  

   slightly 
  backward. 
  The 
  surface 
  is 
  nearly 
  smooth, 
  showing 
  only 
  micro- 
  

   scopic 
  lines 
  of 
  growth. 
  The 
  anterodorsal 
  margin 
  is 
  elongated, 
  slightly 
  

   convex, 
  and 
  slopes 
  very 
  gradually 
  to 
  the 
  rounded 
  anterior 
  end; 
  the 
  

   ventral 
  margin 
  is 
  broadly 
  and 
  evenly 
  convex, 
  but 
  somewhat 
  pinched 
  up 
  

   posteriorly 
  to 
  form 
  a 
  slight 
  emargination 
  below 
  the 
  rostrum, 
  which 
  is 
  

   short, 
  narrow, 
  subtruncate 
  at 
  the 
  tip, 
  aud 
  is 
  defined 
  by 
  a 
  slight, 
  incon- 
  

   spicuous 
  ridge; 
  the 
  i)ostero-dorsal 
  margin 
  is 
  nearly 
  straight 
  and 
  slopes 
  

   rapidly 
  to 
  the 
  upper 
  angle 
  of 
  the 
  rostrum. 
  The 
  hinge 
  plate 
  is 
  strong, 
  

   considerably 
  thickened, 
  with 
  a 
  very 
  obtuse 
  angle 
  at 
  the 
  beak; 
  the 
  ante- 
  

   rior 
  portion 
  is 
  the 
  longer 
  with 
  the 
  inner 
  margin 
  convex, 
  and 
  the 
  posterior 
  

   portion 
  is 
  the 
  wider, 
  more 
  oblique, 
  with 
  the 
  inner 
  margin 
  strongly 
  con- 
  

   cave; 
  the 
  plain 
  outer 
  margin 
  is 
  sharp 
  and 
  projects 
  considerably 
  above 
  

   the 
  teeth 
  which 
  are 
  strong, 
  stand 
  nearly 
  erect, 
  and 
  are 
  less 
  V-shaped 
  

   than 
  usual. 
  There 
  are 
  about 
  fifteen 
  in 
  the 
  anterior 
  series, 
  of 
  which 
  

   three 
  or 
  four 
  proximal 
  ones 
  are 
  quite 
  small, 
  and 
  nine 
  stouter 
  ones 
  in 
  the 
  

   posterior 
  series, 
  including 
  one 
  very 
  small 
  one 
  next 
  the 
  beak. 
  The 
  chon- 
  

   drophore 
  is 
  rather 
  small 
  and 
  deep 
  with 
  a 
  distinctly 
  i)rojecting 
  inner 
  

   edge. 
  

  

  Length, 
  3 
  mm. 
  ; 
  height, 
  2 
  mm. 
  

  

  One 
  valve 
  (No. 
  78365), 
  station 
  2689, 
  oft' 
  Marthas 
  Vineyard, 
  in 
  525 
  

   fathoms, 
  1886. 
  

  

  This 
  species 
  seems 
  to 
  be 
  closely 
  allied 
  to 
  L. 
  semen 
  (Smith) 
  from 
  off 
  

   the 
  coast 
  of 
  Brazil 
  (Voyage 
  of 
  the 
  Ghallenf/er), 
  but 
  that 
  si)ecies, 
  although 
  

   of 
  the 
  same 
  size, 
  has 
  fewer 
  teeth, 
  nine 
  of 
  which 
  are 
  said 
  be 
  anterior 
  aud 
  

   twelve 
  posterior. 
  

  

  PORTLANDIA 
  Morch, 
  18S7. 
  

   Portlandia 
  Verrill 
  and 
  Bush, 
  Amer. 
  Journ. 
  Sci., 
  Ill, 
  pp. 
  .o4, 
  ()2, 
  January, 
  1897. 
  

  

  Type. 
  — 
  Portlandia 
  arctica 
  (Gray) 
  1819 
  = 
  Le<Ja 
  porilandica 
  (Hitchcock). 
  

  

  We 
  consider 
  this 
  a 
  distinct 
  genus, 
  but 
  would 
  restrict 
  it 
  to 
  the 
  orig- 
  

   inal 
  type, 
  unless 
  a 
  few 
  species, 
  which 
  we 
  have 
  not 
  seen, 
  should 
  prove 
  to 
  

   behmg 
  to 
  it. 
  In 
  any 
  case 
  it 
  does 
  not 
  appear 
  that 
  any 
  of 
  the 
  northern 
  

   species 
  of 
  Europe 
  and 
  America 
  that 
  have 
  been 
  referred 
  to 
  it 
  are 
  really 
  

   closely 
  allied 
  to 
  the 
  type. 
  In 
  many 
  respects 
  this 
  genus 
  is 
  intermediate 
  

   between 
  Leda 
  and 
  Yoldia. 
  In 
  its 
  closed 
  shell, 
  definite 
  rostrum, 
  etc., 
  

   it 
  agrees 
  more 
  nearly 
  with 
  the 
  former, 
  but 
  in 
  general 
  outline, 
  with 
  the. 
  

   latter. 
  

  

  