﻿Rang! 
  a 
  cuneata 
  Gray 
  (wedge-shaped.) 
  

  

  cuneata 
  nasuta 
  Pall 
  (with 
  a 
  shuTd- 
  

   it 
  is 
  more 
  rostrate 
  than 
  the 
  ty- 
  

  

  177 
  

   shell 
  "bears 
  a 
  rough 
  

   resemhlanoe 
  to 
  a 
  

   duck's 
  "beak, 
  accord- 
  

   ing 
  to 
  Ghenu. 
  Common 
  

   name: 
  Duck 
  Shells.) 
  

   (Pern.) 
  

  

  e) 
  Genus 
  Rangia 
  Desmou 
  - 
  - 
  

   lins 
  18 
  52. 
  (Named 
  af- 
  

   ter 
  Sander 
  Rang.) 
  

   Also 
  called 
  Genus 
  

   Gnath 
  o 
  don 
  Gray 
  1851 
  . 
  

   (Gr. 
  gnathos, 
  jaw 
  — 
  

   odous, 
  odont-, 
  tooth. 
  

   "Peculiar 
  hooked 
  or 
  

   .j 
  aw- 
  shaped 
  anterior 
  

   lateral." 
  Dall.) 
  

   Gnathodon 
  is 
  masc. 
  

   Rangia 
  is 
  fe 
  m. 
  ) 
  

  

  2. 
  Family 
  Mesodesmatidae 
  . 
  (Gr, 
  raesos, 
  middle, 
  in 
  the 
  middle 
  ^- 
  desma, 
  

   a 
  band, 
  ligament. 
  Ligament 
  mostly 
  internal, 
  b 
  etween 
  the 
  hinge- 
  

   teeth. 
  ) 
  

  

  Mesodesma 
  arctatum 
  Conrad 
  (pressed, 
  com- 
  

   pressed; 
  lateral 
  teeth 
  compressed; 
  be 
  al-cs 
  

   a) 
  Genus 
  Mesodesma 
  Pes 
  - 
  ' 
  very 
  slightly 
  elevated.) 
  

  

  hayes 
  18 
  50. 
  (Ile'uter. 
  )) 
  Mesodesma 
  deauratum 
  Turton 
  (gilded; 
  "sur- 
  

  

  I 
  face 
  covered 
  by 
  a 
  coarse, 
  dusky 
  brov/n 
  

   ! 
  epidermis." 
  Gould 
  & 
  Binney.) 
  

  

  Rangia 
  

  

  nose; 
  

  

  pical 
  cuneata.) 
  

   Rangia 
  flexuosa 
  Conrad 
  (bent; 
  posterior 
  

  

  end 
  is 
  flexed.) 
  

  

  b) 
  Genus 
  

  

  1822. 
  

  

  Eryilia 
  

   ITat. 
  

  

  Turton 
  

  

  ervilia, 
  I 
  

  

  a 
  small 
  lentil 
  (seed 
  : 
  

   of 
  the 
  leguminous 
  ' 
  

   plant.) 
  Lentil- 
  shapedj 
  

   Lentil 
  shell. 
  Fem. 
  ) 
  

  

  Ervilia 
  concentrica 
  Gould 
  (concentric; 
  

   with 
  concentric 
  lines, 
  though 
  weak.) 
  

  

  Ervilia 
  nitens 
  Montagu 
  (shining, 
  lustroui 
  

   white 
  usually 
  v/ith 
  pink 
  spots.) 
  

  

  Ervi 
  l 
  ia 
  rostratu 
  l 
  a 
  Rehder 
  (somewhat 
  ros- 
  

   trate; 
  posterior 
  end 
  is 
  slightly 
  ros- 
  

   trate, 
  pointed.) 
  

  

  Family 
  Hiatellidae 
  . 
  (Lat, 
  hiatus, 
  a 
  gap, 
  aperture. 
  Shells 
  gaping.) 
  

   Formerly 
  known 
  as 
  F 
  amily 
  Saxicavidae 
  (Lat. 
  saxum, 
  a 
  rock 
  — 
  cavare, 
  

   to 
  hollow. 
  They 
  are 
  stone 
  borers.] 
  

  

  a) 
  genuB 
  Hiatella 
  Dau- 
  

  

  tymology 
  

   Both 
  are 
  

  

  above, 
  

   fem.) 
  

  

  Hiatella 
  arctica 
  Linni 
  (Arctic; 
  ranges 
  

  

  from 
  Greenland 
  to 
  the 
  V/est 
  Indies.) 
  

   Hiatella 
  pholadis 
  Linne 
  (Gr. 
  pholas,pho- 
  

  

  lados, 
  lurking 
  in 
  a 
  hole) 
  is 
  the 
  same 
  

  

  as 
  arctica.) 
  

   Hiat 
  e 
  lla 
  azaria 
  Dall 
  (derived 
  from 
  Gr. 
  

  

  aza, 
  dirt, 
  mould 
  on 
  things; 
  covered 
  witl; 
  

  

  strong 
  epidermis.) 
  

   Hiatel 
  la 
  stri 
  ata 
  Fleuriau 
  (with 
  striae.) 
  

  

  b) 
  

  

  G 
  e 
  nus 
  Cyr 
  t 
  odaria 
  

   TPaudi 
  n 
  1799) 
  Cuvie 
  r 
  ^ 
  

   ISOoTTGr. 
  cyrtos,con-i 
  

   vex, 
  curved, 
  arched 
  j 
  

   -I- 
  deros, 
  long.Daudin' 
  

   named 
  it 
  Cyrtodaire. 
  

  

  Cyrtodaria 
  siliqua 
  Spengler 
  (Lat. 
  a 
  pod, 
  

   husk; 
  like 
  a 
  pod, 
  a 
  Siliqua.) 
  

  

  C 
  yrtodaria 
  kurriana 
  Dunker 
  ( 
  found 
  in 
  

   arctic 
  waters. 
  Named 
  for 
  Professor 
  Kurr 
  

   of 
  Stuttgart, 
  Dunker' 
  s 
  friend.) 
  

  

  