﻿NO. 
  1139. 
  DEEP-WATEB 
  MOLLVSCA—VEBRILL 
  AND 
  BUSH. 
  861 
  

  

  But 
  one 
  specimen 
  from 
  station 
  199, 
  off 
  Thatchers 
  Island, 
  in 
  98 
  

   fathoms, 
  1878, 
  has 
  been 
  referred 
  to 
  this 
  species, 
  besides 
  the 
  type 
  

   specimens 
  (No. 
  38420) 
  station 
  1093, 
  off 
  Marthas 
  Vineyard, 
  in 
  349 
  

   iathoms, 
  1882. 
  

  

  YOLDIELLA 
  Verrill 
  and 
  Bush, 
  1897. 
  

   Yoldiella 
  Yerrill 
  and 
  Bush, 
  Amer. 
  Journ. 
  Sci., 
  Ill, 
  pp. 
  55, 
  63, 
  January, 
  1897. 
  

  

  Type. 
  — 
  Yoldiella 
  Jucida 
  (Lovcmi). 
  

  

  This 
  group 
  inckides 
  a 
  large 
  number 
  of 
  small, 
  mostly 
  deep-sea 
  species 
  

   with 
  glossy, 
  iridescent, 
  ovate, 
  and 
  usually 
  wedge-shaped 
  shells, 
  nearly 
  

   always 
  having 
  a 
  slight 
  antero-ventral 
  sinuosity, 
  which 
  feebly 
  defines 
  

   an 
  obscure, 
  blunt, 
  rostal 
  region, 
  without 
  any 
  definite 
  carinatiou. 
  The 
  

   shells 
  do 
  not 
  gape, 
  but 
  close 
  tightly 
  except 
  that 
  at 
  the 
  rostral 
  angle 
  of 
  

   some 
  species 
  there 
  maybe 
  a 
  slight 
  divergence. 
  The 
  internal 
  cartilage, 
  

   which 
  is 
  often 
  relatively 
  large, 
  occupies 
  a 
  simple 
  notch 
  which 
  inter- 
  

   rupts 
  the 
  hinge-margin 
  more 
  or 
  less 
  completely 
  and 
  generally 
  shows 
  

   externally 
  in 
  a 
  dorsal 
  view; 
  the 
  notch 
  usually 
  terminates 
  within, 
  on 
  

   the 
  inner 
  or 
  inferior 
  surface 
  of 
  the 
  hinge-jjlate 
  and 
  is 
  often 
  bounded 
  

   within 
  by 
  a 
  slight 
  ridge. 
  A 
  weak 
  external 
  ligament 
  is 
  iDresent 
  on 
  the 
  

   postero 
  dorsal 
  margin. 
  A 
  relatively 
  small 
  pallial 
  sinus 
  has 
  been 
  

   observed 
  in 
  several 
  of 
  the 
  species, 
  but 
  is 
  usuallj^ 
  indistinct. 
  The 
  

   siphon 
  tubes, 
  as 
  observed 
  in 
  a 
  few 
  of 
  the 
  species, 
  are 
  slender 
  and 
  

   united 
  for 
  more 
  than 
  half 
  their 
  length. 
  

  

  The 
  following 
  are 
  some 
  of 
  the 
  species 
  : 
  Y. 
  lucida 
  (Loven) 
  Yerrill 
  and 
  

   Bush, 
  T. 
  iris 
  Yerrill 
  and 
  Bush, 
  and 
  var. 
  stricta 
  Yerrill 
  and 
  Bush, 
  

   Y. 
  inflata 
  Yerrill 
  and 
  Bush, 
  Y. 
  inconsjncua 
  Yerrill 
  and 
  Bush, 
  and 
  Y. 
  

   jeffreysi 
  (Hidalgo) 
  Yerrill 
  and 
  Bush, 
  off 
  Cape 
  Hatteras, 
  North 
  Caro- 
  

   lina, 
  northward; 
  T. 
  dissiniiUs 
  Yerrill 
  and 
  Bush, 
  north 
  of 
  Cape 
  Hat- 
  

   teras, 
  North 
  Carolina, 
  northward; 
  Y. 
  fraterna 
  Yerrill 
  and 
  Bush, 
  off 
  

   Chesapeake 
  Bay, 
  northward 
  ; 
  Y. 
  minuscula 
  Yerrill 
  and 
  Bush, 
  and 
  Y. 
  

   fiuhequilaiera 
  Yerrill 
  and 
  Bush, 
  off 
  Delasvare 
  Bay, 
  northward; 
  Y. 
  fri- 
  

   fjida 
  (Torell) 
  Yerrill 
  and 
  Bush, 
  and 
  Y. 
  curta 
  Yerrill 
  and 
  Bush, 
  off 
  Mar- 
  

   thas 
  Yineyard, 
  northward; 
  Y. 
  suhangulata 
  Yerrill 
  and 
  Bush, 
  and 
  

   1'. 
  lenticula 
  (Moller) 
  Yerrill 
  and 
  Bush, 
  var. 
  amhlia 
  Yerrill 
  and 
  Bush, 
  

   Gulf 
  of 
  Maine; 
  Y. 
  expansa 
  (Jeffreys) 
  Yerrill 
  and 
  Bush, 
  off 
  Grand 
  

   Banks; 
  Y.pacMa 
  Yerrill 
  and 
  Bush, 
  southern; 
  Y. 
  hoylei 
  (Smith) 
  Yerrill 
  

   and 
  Bush, 
  North 
  Pacific. 
  

  

  YOLDIELLA 
  LUCIDA 
  (Loven) 
  Verrill 
  and 
  Bush. 
  

   (Plates 
  LXXYII, 
  lig. 
  2; 
  LXXX, 
  tig. 
  3.) 
  

  

  Toldia 
  lucida 
  Lov^N, 
  Index 
  Molluscorum, 
  p. 
  34, 
  1846. 
  

  

  ?Leda 
  ohesa 
  Stimpson, 
  Proc. 
  Boston 
  Soc. 
  Nat. 
  Hist., 
  IV, 
  p. 
  113, 
  1851; 
  Sliells 
  New 
  

  

  Eng., 
  p. 
  10, 
  pi. 
  II, 
  fig. 
  1, 
  1851. 
  

   Leda 
  Jucida 
  Jeffreys, 
  British 
  Conchology, 
  V, 
  p. 
  173, 
  pi. 
  c, 
  fig. 
  1, 
  1869. 
  

   YoJdia 
  ohesa 
  Gould, 
  Rep. 
  on 
  Invert, 
  of 
  Mass., 
  Binuey's 
  ed., 
  p. 
  155, 
  tig. 
  463, 
  1870. 
  

   Leda 
  ohesa 
  Tryon, 
  Amer. 
  Mar. 
  Concli., 
  p. 
  184, 
  pi. 
  xxxviii, 
  figs. 
  500, 
  501, 
  1873. 
  

  

  