﻿96 
  Twenty- 
  eighth 
  Beport 
  o:s" 
  the 
  State 
  Museum. 
  

  

  in 
  number, 
  arch 
  slightly 
  forward, 
  pleural 
  lobes 
  flat 
  for 
  one- 
  

   half 
  the 
  width, 
  where 
  they 
  curve 
  downward 
  with 
  a 
  slope 
  of 
  about 
  

   forty-five 
  degrees 
  to 
  the 
  extremities 
  of 
  the 
  segments, 
  the 
  pleu- 
  

   rae 
  of 
  each 
  segment 
  terminating 
  in 
  blunt 
  extremities, 
  a 
  strong 
  

   pleural 
  groove 
  extends 
  from 
  the 
  anterior 
  inner 
  margin 
  to 
  the 
  

   lower 
  edge 
  of 
  the 
  curve 
  a 
  little 
  back 
  of 
  the 
  center 
  of 
  the 
  pleura. 
  

   Anterior 
  margins 
  of 
  the 
  pleurae 
  depressed, 
  permitting 
  them 
  

   to 
  lap 
  beneath 
  those 
  of 
  the 
  preceding 
  segment 
  when 
  the 
  

   animal 
  was 
  coiled. 
  

  

  Pygidium 
  broadly 
  semicircular, 
  convex, 
  with 
  the 
  anterior 
  

   lateral 
  angles 
  obliquely 
  truncated 
  ; 
  axial 
  lobe 
  subconical, 
  

   extending 
  two-thirds 
  the 
  distance 
  from 
  the 
  anterior 
  to 
  the 
  pos- 
  

   terior 
  margin 
  ; 
  two 
  axial 
  rings 
  cross 
  the 
  anterior 
  third; 
  pleu- 
  

   ral 
  lobes, 
  with 
  the 
  exception 
  of 
  a 
  level 
  triangular 
  space 
  each 
  

   side 
  of 
  the 
  axial 
  lobe, 
  slope 
  rapidly 
  from 
  the 
  axial 
  lobe 
  to 
  the 
  

   margin, 
  slightly 
  concave 
  all 
  around 
  between 
  the 
  triangular 
  

   spaces 
  and 
  the 
  margin 
  ; 
  three 
  well-defined 
  segments 
  besides 
  the 
  

   half-segment 
  joining 
  the 
  thorax, 
  extend 
  outward 
  across 
  the 
  

   triangular 
  spaces 
  and 
  then 
  curve 
  downward 
  and 
  backward, 
  

   increasing 
  in 
  width 
  toward 
  the 
  margin. 
  Surface 
  : 
  glabella, 
  

   cheeks 
  and 
  occipital 
  segment 
  finely 
  tuberculated, 
  the 
  remain- 
  

   ing 
  parts 
  are 
  ornamented 
  with 
  fine 
  waving 
  lamelliform 
  struel 
  

  

  Formation 
  and 
  locality. 
  — 
  Black 
  River 
  Limestone, 
  Trenton 
  

   Group, 
  Quarry 
  of 
  William 
  Buck, 
  Esq., 
  Russia, 
  Herkimer 
  Co., 
  

   N. 
  Y. 
  This 
  species 
  also 
  occurs 
  in 
  the 
  Trenton 
  Limestone 
  at 
  

   Plattsville, 
  Wisconsin. 
  

  

  ASAPHUS 
  Brongotart 
  (1822). 
  

  

  ASAPHUS 
  ROMINGERI 
  n. 
  Sp. 
  

  

  Head 
  semicircular, 
  convex 
  ; 
  margin 
  narrow, 
  concave, 
  with 
  

   a 
  wire-like 
  rim 
  rising 
  somewhat 
  abruptly 
  ; 
  postero-lateral 
  

   angles 
  produced 
  into 
  strong 
  spines, 
  slightly 
  concave 
  upon 
  the 
  

   outer 
  surface. 
  Glabella: 
  central 
  portion 
  obovate, 
  subacute 
  

   behind, 
  broadly 
  rounded 
  in 
  front, 
  separated 
  from 
  the 
  fixed 
  

   cheeks 
  by 
  shallow 
  furrows; 
  two 
  slight, 
  elongate 
  elevations 
  

   extend 
  obliquely 
  forward 
  from 
  each 
  lateral 
  third 
  of 
  the 
  pos- 
  

   terior 
  third 
  of 
  the 
  glabella 
  ; 
  upon 
  the 
  depressed 
  posterior 
  

   portion 
  of 
  the 
  glabella 
  are 
  three 
  tubercles, 
  equidistant 
  between 
  

   the 
  convex 
  obovate 
  portion 
  and 
  the 
  occipital 
  segment, 
  the 
  

   central 
  one 
  rising 
  in 
  a 
  short 
  spine. 
  Occipital 
  segment 
  separ- 
  

  

  