﻿222 
  

  

  NEW 
  YORK 
  STATE 
  MUSEUM 
  

  

  ium 
  ending 
  acutely, 
  faintly 
  trilobate, 
  and 
  strongly 
  ringed 
  both 
  on 
  

   the 
  axial 
  and 
  lateral 
  portions; 
  granulose 
  surface. 
  

  

  Fig. 
  153 
  Homalonotus 
  delpliinocephalus, 
  % 
  natural 
  size 
  

  

  Found 
  rarely 
  in 
  the 
  lower 
  Rochester 
  shale 
  at 
  Niagara, 
  but 
  com- 
  

   mon 
  in 
  the 
  upper 
  shales. 
  Also 
  found 
  at 
  Lockport 
  and 
  elsewhere 
  

  

  (Hall). 
  

  

  Genus 
  illaenus 
  Dalman 
  

  

  [Ety.: 
  lAAaivw, 
  to 
  squint] 
  

  

  (1828. 
  Ucher 
  die 
  Palaeaden, 
  p. 
  51) 
  

  

  Cephalon 
  and 
  pygidium 
  of 
  about 
  the 
  same 
  size, 
  large 
  and 
  convex, 
  

   smooth, 
  semicircular 
  in 
  outline, 
  with 
  the 
  trilobations 
  faintly 
  or 
  not 
  

  

  