﻿Report 
  U. 
  S. 
  F. 
  C. 
  1897. 
  (To 
  face 
  page 
  330.) 
  

  

  Plate 
  IV. 
  

  

  %.7. 
  

  

  ti 
  

  

  Tig.Z. 
  

  

  Tig.S. 
  

  

  DETAILS 
  OF 
  FILTER 
  FOR 
  PONDS 
  USED 
  FOR 
  OYSTER-CULTURE. 
  

   After 
  John 
  A. 
  Ryder. 
  

  

  