﻿48 
  A. 
  F. 
  Foerste 
  — 
  Relations 
  of 
  the 
  

  

  5, 
  1847. 
  The 
  names 
  of 
  genera 
  proposed 
  in 
  other 
  publi- 
  

   cations 
  either 
  have 
  since 
  been 
  found 
  to 
  have 
  been 
  pre- 
  

   occupied 
  or 
  to 
  be 
  synonyms 
  of 
  others 
  already 
  published. 
  

  

  EXPLANATION 
  OF 
  PLATES. 
  

  

  Plate 
  I. 
  

  

  Pig. 
  1. 
  Acroliclias 
  cucullus 
  (Meek 
  and 
  Worthen). 
  A, 
  cranidium 
  ; 
  B, 
  

   lateral 
  view, 
  from 
  Trenton 
  at 
  Hull, 
  opposite 
  Ottawa, 
  Canada; 
  in 
  Narra- 
  

   way 
  collection. 
  C, 
  anterior 
  view 
  of 
  cranidium, 
  from 
  Kimmswick 
  in 
  Balls 
  

   county, 
  Missouri. 
  D, 
  fragment 
  of 
  free 
  cheek, 
  Kimmswick 
  limestone, 
  near 
  

   Batehtown, 
  Illinois 
  (20673, 
  Chicago 
  Univ. 
  Museum). 
  E, 
  pygidium, 
  from 
  

   Trenton 
  in 
  bed 
  of 
  creek 
  at 
  head 
  of 
  Front 
  street, 
  in 
  Hull, 
  Canada; 
  in 
  

   Narraway 
  collection. 
  F, 
  pygidium, 
  in 
  Kimmswick 
  on 
  Sanders 
  Branch, 
  in 
  

   Palis 
  county, 
  Missouri. 
  G, 
  hypostoma, 
  from 
  Kimmswick 
  near 
  Batehtown, 
  

   Illinois 
  (20676, 
  Chicago 
  Univ. 
  Museum). 
  

  

  Fig. 
  2. 
  Acroliclias 
  narraway 
  i 
  Foerste. 
  Pygidium 
  from 
  Trenton, 
  in 
  

   quarry 
  at 
  Wright's 
  or 
  St. 
  Clovis' 
  dam, 
  near 
  Hull, 
  Canada; 
  in 
  Narraway 
  

   collection. 
  

  

  Fig. 
  3. 
  Acroliclias 
  trentonensis 
  (Conrad). 
  A, 
  cranidium; 
  B, 
  lateral 
  

   view; 
  from 
  Trenton 
  near 
  Iliff's 
  Pond, 
  New 
  Jersey 
  (10371, 
  Chicago 
  Univ. 
  

   Museum). 
  

  

  Fig. 
  4. 
  Acroliclias 
  conifrons 
  (Euedemann). 
  A, 
  glabella; 
  B, 
  lateral 
  

   view; 
  both 
  considerably 
  restored 
  posteriorly. 
  C, 
  pygidium, 
  as 
  interpreted 
  

   by 
  present 
  writer. 
  Type 
  specimens, 
  from 
  the 
  Trenton 
  at 
  Trenton 
  Falls, 
  

   New 
  York 
  (12950-2, 
  Museum, 
  New 
  York 
  State 
  Geol. 
  Survey). 
  

  

  Fig. 
  5. 
  Acroliclias' 
  comutus 
  (Clarke). 
  Cephalon 
  very 
  poorly 
  preserved, 
  

   drawn 
  as 
  interpreted 
  by 
  present 
  writer; 
  the 
  right 
  half 
  probably 
  is 
  almost 
  

   correct; 
  the 
  left 
  half 
  is 
  viewed 
  at 
  the 
  wrong 
  angle 
  to 
  give 
  the 
  correct 
  

   outline 
  for 
  the 
  side 
  lobe 
  of 
  the 
  glabella, 
  but 
  it 
  gives 
  a 
  fair 
  idea 
  of 
  the 
  

   location 
  and 
  size 
  of 
  the 
  palpebral 
  lobe. 
  The 
  tips 
  of 
  the 
  pleural 
  segments 
  

   on 
  the 
  right 
  side 
  of 
  the 
  thorax, 
  and 
  almost 
  the 
  entire 
  length 
  of 
  the 
  seg- 
  

   ments 
  on 
  the 
  left 
  side, 
  are 
  restored. 
  There 
  are 
  10 
  pleural 
  segments. 
  The 
  

   pygidium 
  is 
  well 
  preserved. 
  Type 
  specimen, 
  from 
  the 
  Trenton 
  at 
  Trenton 
  

   Falls, 
  New 
  York 
  (13703-1, 
  Museum, 
  New 
  York 
  State 
  Geol. 
  Survey). 
  

  

  Plate 
  II. 
  

  

  Fig. 
  1. 
  Acrolichas 
  jukesii 
  (Billings). 
  A, 
  cephalon; 
  B, 
  cranidium; 
  

   from 
  Chazyan 
  at 
  Cow 
  Head, 
  Newfoundland, 
  (Pal. 
  Foss., 
  1, 
  1865, 
  p. 
  335, 
  

   fig. 
  323a; 
  p. 
  282, 
  fig. 
  269b). 
  

  

  Fig. 
  2. 
  Acroliclias 
  robbinsi 
  (Ulrich). 
  Cranidium, 
  from 
  the 
  Prosser, 
  

   near 
  Wykoff, 
  Minnesota 
  (Amer. 
  Geol., 
  10, 
  p. 
  271, 
  fig. 
  la, 
  1892). 
  

  

  Fig. 
  3. 
  Acroliclias 
  bicornis 
  (Ulrich). 
  Cranidium, 
  from 
  Maquoketa 
  at 
  

   Spring 
  Valley, 
  Minnesota 
  (Amer. 
  Geol., 
  10, 
  p. 
  272, 
  fig. 
  2a, 
  1892). 
  

  

  Fig. 
  4. 
  Acroliclias 
  rhinoceras 
  (Slocom). 
  Glabella, 
  from 
  Maquoketa 
  at 
  

   Elgin, 
  Iowa 
  (Field 
  Mus. 
  Nat. 
  Hist., 
  Geol. 
  Ser., 
  4, 
  No. 
  3, 
  1913, 
  PI. 
  15, 
  

   fig. 
  5). 
  

  

  Fig. 
  5. 
  Acrolichas 
  cf. 
  conifrons 
  Euedemann. 
  A, 
  cranidium; 
  B, 
  lateral 
  

   view; 
  from 
  Kimmswick, 
  near 
  Batehtown, 
  Illinois 
  (20674, 
  Chicago 
  Univ. 
  

   Museum). 
  

  

  Fig. 
  6. 
  Eemiarges 
  paulianus 
  (Clarke). 
  A, 
  cranidium; 
  B, 
  lateral 
  view; 
  

   C, 
  second 
  cranidium 
  with 
  broken 
  neck 
  ring, 
  from 
  Trenton 
  near 
  Hull, 
  

   Canada 
  (in 
  Narraway 
  collection). 
  

  

  Fig. 
  7. 
  Acrolichas 
  clermontensis 
  (Slocom). 
  Glabella, 
  from 
  Maquoketa, 
  

   at 
  Clermont, 
  Iowa 
  (collected 
  by 
  A. 
  "W. 
  Slocom). 
  

  

  Fig. 
  8. 
  Flatylichas{?) 
  lialli 
  (Foerste). 
  A, 
  cranidium 
  and 
  part 
  of 
  

   thorax 
  (Bull. 
  Lab. 
  Denison 
  Univ., 
  3, 
  p. 
  118, 
  PI. 
  XIII, 
  fig. 
  4, 
  1888) 
  ; 
  B, 
  

  

  