﻿GLOCHIDIA 
  OF 
  FRESH-WATER 
  MUSSELS. 
  9 
  

  

  Glochidium 
  subtriangular 
  iii 
  shape; 
  hinge 
  Ime 
  long 
  and 
  rather 
  

   evenly 
  curved; 
  depth 
  greater 
  than 
  length; 
  size 
  medium, 
  0.150 
  by 
  

   0.160 
  mm. 
  

  

  In 
  this 
  species 
  the 
  glochidium 
  seems 
  to 
  be 
  intermediate 
  in 
  shape 
  

   between 
  examples 
  of 
  the 
  Anodonta 
  group 
  on 
  the 
  one 
  hand 
  and 
  cer- 
  

   tain 
  species 
  of 
  the 
  Lamj^silis-Quadrula 
  group 
  on 
  the 
  other, 
  best 
  rep- 
  

   resented 
  m 
  the 
  former 
  by 
  Alasmidonta 
  calceola, 
  and 
  in 
  the 
  latter 
  by 
  

   such 
  species 
  as 
  Quadrula 
  ehena, 
  etc. 
  Compared 
  with 
  Vnio 
  gihhosa 
  

   it 
  is 
  more 
  circular 
  in 
  outlme, 
  if 
  we 
  except 
  the 
  pointed 
  ventral 
  margin, 
  

   and 
  has 
  a 
  shorter, 
  more 
  curved 
  hinge 
  hne. 
  It 
  is 
  an 
  aberrant 
  type 
  

   related 
  to 
  Margaritana 
  margaritifera. 
  Host 
  unknown. 
  

  

  EXPLANATION 
  OF 
  FIGURES. 
  (Plate 
  I.) 
  

  

  Fig. 
  1. 
  Anodonta 
  suborbiculata. 
  

  

  Fig. 
  2. 
  Lampsilis 
  muUiradiata. 
  

  

  Fig. 
  3. 
  Lampsilis 
  parva. 
  

  

  Fig. 
  4. 
  Lampsilis 
  picta. 
  

  

  Fig. 
  5, 
  5a. 
  Lampsilis 
  purpurata. 
  

  

  Fig. 
  6. 
  Lampsilis 
  ventricosa 
  satura. 
  

  

  Fig. 
  7. 
  Margaritana 
  monodonta. 
  

  

  Fig. 
  8. 
  Obovaria 
  circulus. 
  

  

  Fig. 
  9. 
  Quadrula 
  coccinea. 
  

  

  Fig. 
  10. 
  Quadrula 
  hcros. 
  

  

  Fig. 
  11. 
  Quadrula 
  lachrymosa. 
  

  

  Fig. 
  12. 
  Quadrula 
  obliqua. 
  

  

  Fig. 
  13. 
  Unio 
  crassidens. 
  

  

  Fig. 
  14. 
  Lampsilis 
  breviculus 
  brittsi. 
  

  

  Fig. 
  15. 
  Lampsilis 
  lienosa 
  unicostata. 
  

  

  