﻿VERTEBRA.TES. 
  161 
  

  

  the 
  inner 
  angle 
  of 
  the 
  coronal 
  ridge 
  to 
  the 
  inrolled 
  outer 
  extremity, 
  

   about 
  11.5 
  mm 
  ; 
  greatest 
  breadth 
  across 
  inner 
  margin, 
  9 
  mm. 
  

  

  As 
  yet 
  other 
  forms 
  which 
  were 
  probably 
  associated 
  with 
  the 
  above 
  

   tooth 
  have 
  not 
  been 
  recognized. 
  Indeed 
  it 
  is 
  only 
  within 
  a 
  recent 
  

   date 
  that 
  the 
  Warsaw 
  beds 
  have 
  afforded 
  many 
  fish 
  remains, 
  and 
  

   in 
  most 
  instances 
  these 
  represent 
  forms 
  peculiar 
  to 
  the 
  formation. 
  

  

  Geological 
  position 
  and 
  locality: 
  Warsaw 
  shaly 
  limestone, 
  Golden 
  

   Bluffs, 
  near 
  Warsaw, 
  HI. 
  

  

  Deltodopsis 
  St. 
  Ludovici, 
  St. 
  J. 
  and 
  W. 
  

  

  PL 
  XI, 
  Fig. 
  2-6. 
  

  

  Mandibular 
  posterior 
  teeth 
  depressed, 
  triangular 
  in 
  general 
  outline, 
  

   moderately 
  arched 
  longitudinally 
  and 
  inrolled. 
  Antero 
  -lateral 
  border 
  

   comprising 
  a 
  little 
  more 
  than 
  one-third 
  the 
  extent 
  of 
  the 
  tooth 
  

   along 
  the 
  coronal 
  ridge, 
  gently 
  curved 
  from 
  within 
  outward, 
  basal 
  

   rim 
  slightly 
  furrowed 
  and 
  bordered 
  by 
  the 
  distinct, 
  narrow, 
  inbeveled 
  

   enamel 
  fold 
  ; 
  inner 
  margin 
  in 
  front 
  diverging 
  at 
  a 
  slight 
  angle 
  from 
  

   the 
  anterior 
  angle 
  to 
  the 
  base 
  of 
  the 
  coronal 
  ridge, 
  round 
  which 
  it 
  

   is 
  sharply 
  curved 
  with 
  a 
  slightly 
  concave 
  course 
  to 
  the 
  acute 
  pos- 
  

   terior 
  angle 
  of 
  the 
  alate 
  expansion, 
  inferiorly 
  inbeveled; 
  postero- 
  

   lateral 
  border 
  gently 
  arched, 
  gradually 
  converging 
  toward 
  the 
  sud- 
  

   denly 
  inrolled 
  outer 
  extremity, 
  the 
  narrow 
  inbeveled 
  enamel 
  fold 
  

   distinctly 
  defined 
  from 
  the 
  nearly 
  vertical 
  channeled 
  basal 
  border. 
  

   Coronal 
  prominence 
  culminating 
  in 
  an 
  obtusely 
  rounded 
  ridge 
  near 
  

   the 
  median 
  line, 
  anterior 
  broad 
  slope 
  nearly 
  plane 
  or 
  slightly 
  con- 
  

   vex, 
  more 
  abruptly 
  sloping 
  into 
  the 
  depression 
  on 
  the 
  opposite 
  

   side, 
  which 
  is 
  bordered 
  by 
  the 
  moderately 
  upraised 
  narrow 
  alate 
  

   expansion 
  of 
  the 
  postero-lateral 
  border. 
  Crown 
  surface 
  minutely 
  

   and 
  somewhat 
  irregularly 
  punctate, 
  unworn 
  surfaces 
  showing 
  

   numerous 
  delicate 
  transverse 
  furrows 
  parallel 
  with 
  the 
  inner 
  margin 
  

   and 
  producing 
  a 
  slight 
  undulated 
  appearance; 
  in 
  some 
  examples 
  

   the 
  exfoliated 
  enamel 
  reveals 
  a 
  surface 
  delicately 
  striated 
  by 
  wavy 
  

   threads 
  holding 
  the 
  same 
  course 
  as 
  the 
  undulations. 
  A 
  tooth 
  of 
  

   medium 
  ?size 
  measures 
  along 
  the 
  articular 
  anterior 
  border 
  to 
  

   point 
  of 
  inrollment 
  8.5 
  mm; 
  transverse 
  diameter 
  across 
  inner 
  mar- 
  

   gin 
  13.5 
  mm; 
  length 
  along 
  crest 
  of 
  coronal 
  ridge 
  19 
  mm. 
  

  

  Mandibular 
  median 
  tooth 
  subtrapezoidal 
  in 
  outline, 
  moderately 
  

   arched 
  longitudinally, 
  outer 
  extremity 
  strongly 
  inrolled 
  spirally 
  for- 
  

   ward. 
  Postero-lateral 
  border 
  gently 
  curved 
  conforming 
  to 
  the 
  

   n 
  

  

  