﻿4 
  GLOCHIDIA 
  OF 
  FRESH-WATER 
  MUSSELS. 
  

  

  sequence 
  in 
  the 
  key. 
  The 
  present 
  method 
  of 
  describing 
  conforms 
  to 
  

   that 
  used 
  previously, 
  this 
  paper 
  being 
  intended, 
  in 
  fact, 
  to 
  supple- 
  

   ment 
  the 
  former 
  one.*^ 
  Any 
  information 
  to 
  be 
  of 
  practical 
  use 
  must 
  

   be 
  available 
  to 
  all 
  investigators, 
  and 
  in 
  the 
  present 
  state 
  of 
  our 
  

   knowledge 
  of 
  mussel 
  culture 
  the 
  sooner 
  it 
  is 
  made 
  accessible 
  the 
  

   better; 
  hence 
  the 
  appearance 
  of 
  these 
  papers 
  from 
  time 
  to 
  time. 
  

  

  In 
  the 
  preparation 
  of 
  material 
  no 
  changes 
  have 
  been 
  made 
  in 
  the 
  

   technique, 
  except 
  that 
  it 
  has 
  been 
  found 
  advisable 
  to 
  stain 
  exclu- 
  

   sively 
  with 
  alcohohc 
  cochineal 
  (Mayer's 
  old 
  formula).^ 
  Light, 
  it 
  has 
  

   been 
  found, 
  plays 
  an 
  important 
  part 
  in 
  the 
  subsequent 
  value 
  of 
  the 
  

   material 
  — 
  strong 
  light, 
  particularly 
  sunlight, 
  bleaching 
  out 
  the 
  glo- 
  

   chidium 
  till 
  its 
  transparency 
  becomes 
  such 
  as 
  to 
  render 
  it 
  worthless. 
  

   For 
  this 
  reason 
  all 
  material, 
  both 
  glochidia 
  and 
  natural 
  infections 
  of 
  

   same, 
  as 
  soon 
  as 
  killed 
  should 
  be 
  stored 
  in 
  a 
  hght-tight 
  receptacle 
  of 
  

   some 
  kind 
  and 
  there 
  retained 
  till 
  stained 
  and 
  momited. 
  

  

  In 
  the 
  descriptions 
  to 
  follow 
  no 
  attempt 
  has 
  been 
  made 
  to 
  arrange 
  

   the 
  species 
  systematically, 
  an 
  alphabetical 
  arrangement 
  being 
  con- 
  

   sidered 
  preferable. 
  

  

  Anodonta 
  suhorhiculata 
  Say. 
  [Fig. 
  1.] 
  

  

  Lake 
  Contrary, 
  St. 
  Joseph, 
  Mo., 
  February 
  20, 
  1913. 
  Collected 
  by 
  

   W. 
  I. 
  Utterback; 
  collection 
  of 
  United 
  States 
  Biological 
  Laboratory, 
  

   no. 
  G-72. 
  

  

  Glochidium 
  of 
  Anodonta 
  type, 
  large, 
  subtriangular 
  in 
  shape, 
  

   with 
  spine 
  at 
  tip 
  of 
  each 
  valve; 
  hinge 
  line 
  straight, 
  long; 
  length 
  

   shghtly 
  greater 
  than 
  depth, 
  0.325 
  by 
  0.320 
  mm. 
  In 
  general 
  outhne 
  

   suhorhiculata 
  closely 
  resembles 
  Anodonta 
  grandis 
  but 
  may 
  be 
  dis- 
  

   tinguished 
  by 
  its 
  smaller 
  size. 
  

  

  Thanks 
  are 
  due 
  Prof. 
  Utterback 
  for 
  his 
  kindness 
  in 
  forwarding 
  

   these 
  glochidia 
  for 
  the 
  station 
  collection. 
  In 
  the 
  vicinity 
  of 
  Fairport 
  

   this 
  species 
  has 
  apparently 
  become 
  extinct 
  in 
  its 
  usual 
  haunts, 
  

   because 
  of 
  the 
  unusually 
  dry 
  summer 
  of 
  1911. 
  During 
  that 
  season 
  

   all 
  the 
  ponds 
  dried 
  up 
  and 
  many 
  dead 
  shells 
  of 
  this 
  species 
  were 
  taken 
  

   from 
  the 
  dry 
  pond 
  bottoms 
  by 
  Mr. 
  H. 
  Walton 
  Clark 
  and 
  the 
  writer. 
  

   Host 
  unknown. 
  

  

  Lampsilis 
  hreviculus 
  hrittsi 
  Simpson. 
  [Fig. 
  14.] 
  

  

  Niangua 
  River, 
  Hahatonka, 
  Mo., 
  August 
  7, 
  1913. 
  Collected 
  by 
  

   W. 
  I. 
  Utterback; 
  collection 
  of 
  United 
  States 
  Biological 
  Laboratory, 
  

   no. 
  G-74. 
  

  

  Lamjysilis 
  type; 
  semielliptical; 
  ventral 
  margin 
  rounded; 
  hinge 
  Hne 
  

   rather 
  short, 
  nearly 
  straight; 
  general 
  outUne 
  of 
  shell 
  constricted 
  at 
  

   either 
  end 
  below 
  hinge 
  line; 
  size 
  large, 
  0.230 
  by 
  0.290 
  mm. 
  

  

  a 
  Surber, 
  op. 
  cit. 
  

  

  t> 
  Lee, 
  Arthur 
  Bolles: 
  The 
  microtomist's 
  vade-mecum. 
  Sixth 
  edition, 
  p. 
  175. 
  London, 
  1905. 
  

  

  