﻿U. 
  S. 
  NATIONAL 
  MUSEUM 
  

  

  PROCEEDINGS, 
  VOL. 
  XX 
  PL. 
  LXX 
  

  

  Crayfishes. 
  

  

  Fios. 
  1-3. 
  PdrnfttacHs 
  haaxlpri. 
  Firs. 
  4. 
  .'i. 
  Pantfifnciift 
  di/nsnizii. 
  

  

  For 
  explanation 
  of 
  plate 
  see 
  page 
  694. 
  

  

  