﻿878 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM. 
  vol.xx. 
  

  

  minute 
  or 
  nearly 
  abortive, 
  occupying 
  a 
  slight 
  notch 
  in 
  the 
  dorsal 
  

   margin 
  under 
  the 
  beak, 
  external 
  to 
  the 
  series 
  of 
  teeth, 
  which 
  are 
  inter- 
  

   rupted 
  only 
  by 
  a 
  small, 
  thin 
  edentulous 
  space. 
  Pallial 
  sinus 
  small. 
  

   Siphon 
  tubes 
  short. 
  Labial 
  palpi 
  large, 
  broad, 
  crescent-shaped, 
  with 
  

   long 
  tentacular 
  appendages. 
  Gills 
  small, 
  triquetral. 
  

  

  We 
  consider 
  this 
  group 
  worthy 
  of 
  generic 
  rank. 
  It 
  appears 
  to 
  be 
  

   njore 
  nearly 
  allied 
  to 
  MuUetia 
  than 
  to 
  Yoldia 
  or 
  Leda. 
  We 
  can 
  iind 
  no 
  

   generic 
  characters 
  to 
  distinguish 
  DalPs 
  typical 
  species 
  (i\r. 
  corjm^e** 
  /a) 
  

   from 
  N.punio, 
  which 
  was 
  the 
  type 
  of 
  the 
  section, 
  Saturnia, 
  proposed 
  

   by 
  Seguenza. 
  They 
  agree 
  closely 
  in 
  form, 
  external 
  sculpture, 
  arrange- 
  

   ment 
  of 
  the 
  teeth, 
  and 
  structure 
  of 
  ligament 
  and 
  resilium. 
  The 
  name, 
  

   Saturnia, 
  being 
  preoccupied 
  by 
  Schrank, 
  1802, 
  we 
  have 
  adopted 
  Ball's 
  

   name 
  for 
  both 
  of 
  his 
  sections. 
  

  

  The 
  following 
  species 
  appear 
  to 
  belong 
  here: 
  

  

  N'. 
  corpulenta 
  Dall 
  (type), 
  and 
  N. 
  quadrangidaris 
  (Ball), 
  West 
  Indies; 
  

   N.sericea 
  (Jeffreys), 
  Ireland 
  and 
  Portugal; 
  iV".^«fsio 
  (Philippi), 
  Medi- 
  

   terranean 
  and 
  West 
  Indies; 
  N. 
  suhovata 
  Verrill 
  and 
  Bush, 
  from 
  off 
  

   Cape 
  Hatteras, 
  North 
  Carolina, 
  northward. 
  

  

  NEILONELLA 
  SUBOVATA 
  Verrill 
  and 
  Bush. 
  

   (Plates 
  LXXX, 
  fig. 
  10; 
  LXXXII, 
  figs. 
  3, 
  4.) 
  

  

  Yoldia 
  aericca 
  Jeffreys, 
  var, 
  striolata 
  Verrill, 
  Traus. 
  Conn. 
  Acad., 
  VI, 
  p. 
  226, 
  

   1884. 
  — 
  Verrill, 
  Ex^pl. 
  Albatross, 
  Report 
  U. 
  S. 
  Com. 
  Fish 
  and 
  Fisberie.s 
  for 
  

   1883, 
  p. 
  576, 
  1885. 
  

  

  Neilonella 
  suhovata 
  Verrill 
  and 
  Busn, 
  Amer. 
  Journ. 
  Sci., 
  Ill, 
  p. 
  57, 
  figs. 
  7, 
  8, 
  22, 
  

   January, 
  1897. 
  

  

  Shell 
  somewhat 
  swollen, 
  subovate, 
  with 
  the 
  dorsal 
  margin 
  angulated 
  

   and 
  the 
  umbos 
  somewhat 
  prominent. 
  The 
  antero-dorsal 
  margin 
  is 
  

   somewhat 
  convex, 
  pinched 
  up 
  at 
  the 
  edge, 
  and 
  sloped 
  gradually 
  to 
  the 
  

   evenly 
  rounded 
  anterior 
  end 
  ; 
  ventral 
  margin 
  is 
  broadly 
  and 
  nearly 
  

   evenly 
  rounded 
  throughout, 
  without 
  any 
  sinuosity, 
  and 
  forms 
  a 
  blunt 
  

   point 
  at 
  its 
  junction 
  with 
  the 
  i)Ostero-dorsal 
  margin, 
  which 
  is 
  nearly 
  

   straight 
  or 
  slightly 
  convex 
  for 
  the 
  greater 
  part 
  of 
  its 
  length, 
  with 
  the 
  

   edge 
  thin 
  and 
  pinched 
  up. 
  The 
  umbos 
  are 
  somewhat 
  prominent 
  and 
  

   the 
  beaks 
  curve 
  strongly 
  inward 
  and 
  incline 
  a 
  little 
  backward 
  at 
  the 
  

   tip. 
  The 
  ligament 
  is 
  well 
  developed, 
  dark 
  brown, 
  and 
  as 
  seen 
  in 
  a 
  

   dorsal 
  view, 
  fills 
  a 
  narrow, 
  lanceolate 
  excavation 
  in 
  the 
  margin 
  just 
  

   behind 
  the 
  beaks. 
  In 
  an 
  interior 
  view 
  it 
  is 
  conspicuous 
  behind 
  the 
  

   beaks 
  and 
  occupies 
  a 
  curved 
  notch 
  immediately 
  under 
  them, 
  and 
  ex- 
  

   tends 
  forward 
  for 
  a 
  short 
  distance 
  in 
  a 
  .thin, 
  marginal 
  groove. 
  The 
  

   resilium 
  is 
  abortive 
  or 
  nearly 
  so 
  ; 
  in 
  many 
  cases 
  it 
  appears 
  to 
  be 
  repre- 
  

   sented 
  by 
  a 
  minute 
  black 
  sj^eck, 
  adherent 
  to 
  the 
  ligament, 
  and 
  occu- 
  

   pying 
  a 
  minute 
  indentation 
  in 
  the 
  edge 
  of 
  the 
  hinge-margin 
  directly 
  

   beneath 
  the 
  beak, 
  external 
  to 
  the 
  series 
  of 
  teeth. 
  The 
  hinge-margin 
  is 
  

   broad 
  and 
  rather 
  strong, 
  becoming 
  very 
  narrow 
  below 
  the 
  beak 
  but 
  

   without 
  a 
  distinct 
  notch 
  or 
  choudrophorej 
  the 
  posterior 
  portion 
  is 
  

  

  