﻿U. 
  S. 
  NATIONAL 
  MUSEUM 
  

  

  PROCEEDINGS, 
  VOL. 
  67, 
  ART. 
  I 
  PL. 
  7 
  

  

  .52 
  "' 
  '50 
  

  

  Structural 
  Details 
  of 
  Metapterus 
  and 
  Ischnonyctes 
  

  

  For 
  explanation 
  o- 
  plate 
  see 
  page 
  148 
  

  

  14!) 
  

  

  