﻿EXPLANATION 
  OF 
  PLATES. 
  

  

  PLATE 
  I. 
  

  

  Coccosteus? 
  halmodeus, 
  sp. 
  no 
  v. 
  

  

  Fig. 
  1. 
  — 
  The 
  dorsal 
  aspect 
  of 
  the 
  specimen 
  described, 
  showing 
  what 
  

   is 
  retained 
  of 
  the 
  cranium 
  and 
  mandibles. 
  The 
  distinction 
  between 
  the 
  

   sensory 
  canals 
  and 
  sutures 
  will 
  be 
  best 
  elucidated 
  by 
  comparison 
  with 
  

   the 
  diagram 
  given 
  upon 
  page 
  162. 
  

  

  Fig. 
  2. 
  — 
  A 
  plate 
  believed 
  to 
  be 
  a 
  dorso-median 
  shield 
  of 
  the 
  same 
  

   species. 
  If 
  this 
  is 
  the 
  correct 
  interpretation 
  of 
  its 
  nature, 
  it 
  has 
  been 
  

   drawn 
  in 
  a 
  reversed 
  position. 
  The 
  plate 
  is 
  considerably 
  broken 
  and 
  in 
  

   such 
  a 
  manner 
  as 
  to 
  demonstrate 
  the 
  presence 
  of 
  a 
  strong 
  internal 
  

   median 
  ridge, 
  which 
  is 
  deepest 
  at 
  the 
  anterior 
  (posterior) 
  extremity. 
  

   The 
  surface 
  shows 
  no 
  satisfactory 
  evidence 
  of 
  sutures. 
  

   t 
  Marcellus 
  shales. 
  At 
  825-828 
  feet 
  in 
  the 
  Livonia 
  shaft. 
  

  

  