﻿WALKER 
  : 
  ON 
  MARGAIilTANA 
  MARGAEITJFEEA. 
  145 
  

  

  1881. 
  Wkthekbt 
  (A. 
  G.). 
  "On 
  the 
  Geographical 
  Distribution 
  of 
  

  

  certain 
  Freshwater 
  Mollusks 
  of 
  North 
  America,"- 
  pt. 
  ii 
  : 
  

   Journ. 
  Cin. 
  Soc. 
  IS^at. 
  Hist., 
  1881, 
  separate, 
  pp. 
  1-11. 
  

  

  1882. 
  "The 
  Distribution 
  of 
  M. 
  margaritifera^' 
  : 
  Amer. 
  Nat., 
  

  

  xvi, 
  pp. 
  375-6. 
  

  

  1905. 
  White 
  (C. 
  A.). 
  " 
  The 
  Ancestral 
  Origin 
  of 
  the 
  North 
  American 
  

  

  Unionidse 
  " 
  : 
  Smithsonian 
  Misc. 
  Coll., 
  xlviii, 
  pp. 
  75-88. 
  

   1895. 
  Whiteaves 
  (J. 
  F.). 
  " 
  Notes 
  on 
  Recent 
  Canadian 
  Unionidae 
  " 
  : 
  

  

  Canadian 
  Record 
  of 
  Science, 
  1895, 
  pp. 
  250-63. 
  

   1901. 
  "Notes 
  on 
  some 
  Land 
  and 
  Freshwater 
  Moll 
  u 
  sea 
  from 
  

  

  Fort 
  Chimo, 
  TJngava 
  Bay, 
  Ungava 
  " 
  : 
  Ott. 
  Nat., 
  xiv, 
  

  

  pp. 
  221-3. 
  

  

  1906. 
  "Notes 
  on 
  some 
  Land 
  and 
  Freshwater 
  Shells 
  from 
  

  

  British 
  Columbia": 
  Ott. 
  Nat., 
  xx, 
  pp. 
  115-19. 
  

  

  EXPLANATION 
  OF 
  PLATE 
  II. 
  

  

  The 
  circular 
  dots 
  indicate 
  the 
  present 
  range 
  of 
  M. 
  margaritifera 
  in 
  North 
  America. 
  

   The 
  triangular 
  dots 
  that 
  of 
  M. 
  moiiodonta. 
  

   The 
  square 
  dots 
  that 
  of 
  31. 
  Hembeli. 
  

   The 
  X 
  that 
  of 
  M. 
  dtcumbens. 
  

  

  