﻿58 
  Yerrill 
  and 
  Bush 
  — 
  Genera 
  of 
  Ledidce 
  and 
  Nuculidoe. 
  

  

  Subfamily 
  Tindarin^, 
  nov. 
  

  

  Cucullellinm 
  (pars) 
  Fischer, 
  Man. 
  Conch., 
  p. 
  981. 
  Ctenodontidoe 
  

   Dall 
  (pars), 
  Trans. 
  Wagner 
  Free 
  Inst., 
  iii, 
  p. 
  515, 
  1895. 
  

  

  In 
  this 
  group 
  the 
  shell 
  is 
  short-ovate 
  or 
  veneriform, 
  with 
  the 
  

   posterior 
  end 
  the 
  longer. 
  The 
  beaks 
  turn 
  forward. 
  The 
  internal 
  

   cartilage 
  is 
  wanting. 
  The 
  external 
  ligament 
  is 
  well-developed 
  

   and 
  prominent. 
  The 
  teeth 
  are 
  numerous, 
  v-shaped, 
  the 
  two 
  

   series 
  are 
  frequently 
  continuous 
  proximally. 
  There 
  is 
  neither 
  

   pallial 
  sinus 
  nor 
  true 
  siphons. 
  The 
  mantle 
  is 
  broadly 
  open 
  vent- 
  

   rally, 
  but 
  there 
  is 
  a 
  separate 
  anal 
  or 
  efferent 
  orifice, 
  surrounded 
  

   by 
  small 
  sense 
  papillae. 
  The 
  palpi 
  are 
  large, 
  with 
  long 
  slender 
  

   appendages. 
  Foot 
  with 
  a 
  large, 
  terminal, 
  crenulated 
  disk. 
  

  

  This 
  group 
  agrees 
  with 
  Malletinm 
  in 
  having 
  no 
  internal 
  cartil- 
  

   age, 
  but 
  there 
  are, 
  in 
  the 
  latter, 
  well-developed 
  siphons 
  and 
  a 
  

   pallial 
  sinus. 
  

  

  Numerous 
  Palaeozoic 
  species 
  referred 
  to 
  the 
  genus 
  Palceoneilo 
  

   probably 
  belong 
  to 
  or 
  near 
  this 
  group. 
  Some 
  of 
  the 
  species* 
  

   from 
  the 
  American 
  Devonian 
  rocks 
  can 
  hardly 
  be 
  distinguished 
  

   from 
  Tindaria 
  by 
  any 
  important 
  structural 
  characters. 
  It 
  is 
  

   probable 
  that 
  Nuculites 
  and 
  several 
  related 
  genera 
  also 
  belong 
  

   to 
  this 
  division, 
  for 
  they 
  have 
  an 
  external 
  cartilage 
  and 
  no 
  

   chondrophore. 
  In 
  these 
  genera 
  the 
  plain 
  transverse 
  teeth 
  are 
  

   very 
  numerous 
  and 
  more 
  simple 
  than 
  in 
  the 
  modern 
  genera, 
  

   seldom 
  showing 
  any 
  trace 
  of 
  the 
  acute 
  v-shaped 
  form. 
  

  

  Mr. 
  Dall 
  has 
  proposed 
  the 
  family 
  Ctenodontidw 
  to 
  include 
  the 
  

   extinct 
  genera 
  above 
  named 
  and 
  others, 
  but 
  it 
  is 
  doubtful 
  whether 
  

   Ctenodonta 
  itself 
  belongs 
  here. 
  Zittell 
  and 
  others 
  refer 
  it 
  to 
  

   Arcidae. 
  

  

  Tindaria 
  Bellardi. 
  Figures 
  10, 
  20, 
  21. 
  Type 
  T. 
  arata 
  Bellardi. 
  

  

  Several 
  recent 
  writers 
  on 
  these 
  shells 
  have 
  regarded 
  Tindaria 
  

   as 
  a 
  subgenus 
  of 
  Malletia. 
  In 
  reality 
  they 
  form 
  two 
  widely 
  

   diverse 
  genera. 
  In 
  typical 
  Tindarim 
  the 
  shell 
  is 
  swollen, 
  ovate, 
  

   short, 
  or 
  subcordate, 
  without 
  any 
  rostration, 
  and 
  with 
  prominent 
  

   umbos, 
  with 
  the 
  beaks 
  turned 
  forward. 
  In 
  fact, 
  the 
  shells 
  may 
  be 
  

   described 
  as 
  veneriform. 
  The 
  surface 
  is 
  usually 
  concentrically 
  

   grooved. 
  The 
  series 
  of 
  teeth 
  are 
  often 
  continuous 
  medially. 
  

   There 
  is 
  no 
  pallial 
  sinus. 
  

  

  The 
  following 
  are 
  some 
  of 
  the 
  known 
  species 
  : 
  

  

  T. 
  arata 
  Bellardi, 
  T. 
  solida 
  Seguenza, 
  T. 
  cytherea 
  Dall 
  = 
  T. 
  

   veneriformis 
  Smith, 
  T. 
  amabilis 
  Dall, 
  T. 
  virens 
  Dall, 
  T. 
  acinula 
  

  

  little 
  in 
  front 
  of 
  them. 
  Cartilage 
  minute, 
  marginal. 
  Epidermis 
  without 
  much 
  

   luster, 
  either 
  greenish 
  yellow 
  or 
  light 
  straw-color. 
  Muscular 
  impressions 
  faint; 
  

   sometimes 
  a 
  distinct 
  angular 
  pallial 
  sinus 
  is 
  visible. 
  

  

  Length, 
  6-5 
  mm 
  ; 
  height, 
  4-6 
  mm 
  ; 
  thickness, 
  about 
  3*5 
  mm 
  . 
  

  

  Found 
  at 
  many 
  stations 
  from 
  off 
  George's 
  Banks 
  to 
  Cape 
  Hatteras, 
  in 
  125 
  to 
  

   1731 
  fathoms, 
  1883-1887. 
  

  

  * 
  For 
  examples 
  see 
  P. 
  constricta 
  Hall, 
  P. 
  plana 
  Hall 
  in 
  Palaeontology 
  of 
  New 
  

   Tork, 
  v, 
  pt. 
  I, 
  pp. 
  333, 
  334, 
  pl.'xlviii, 
  figs. 
  1-28, 
  1885. 
  

  

  