﻿458 
  PKOE. 
  H. 
  G. 
  SEELEY 
  OX 
  THECOSPONDTLTTS 
  HOKXERI. 
  

  

  observe 
  on 
  the 
  sides 
  of 
  this 
  specimen 
  large 
  vertical 
  eminences 
  (fig. 
  1,£), 
  

   which 
  resemble 
  those 
  figured 
  by 
  Prof. 
  Marsh, 
  we 
  might 
  be 
  tempted 
  

   to 
  suppose 
  that 
  here 
  too 
  were 
  intervertebral 
  foramina, 
  were 
  it 
  not 
  that 
  

   a 
  large 
  transverse 
  process 
  (figs. 
  1 
  & 
  2, 
  t 
  a) 
  is 
  preserved 
  which 
  exactly 
  

   fits 
  on 
  to 
  one 
  of 
  them. 
  This 
  transverse 
  process 
  is 
  a 
  cast 
  in 
  sandstone 
  

   without 
  a 
  trace 
  of 
  bony 
  tissue; 
  but, 
  from 
  the 
  sharpness 
  of 
  its 
  contours, 
  

   it 
  assists 
  in 
  demonstrating 
  the 
  conclusion 
  that 
  the 
  bony 
  substance 
  of 
  

   this 
  sacrum 
  must 
  have 
  been 
  of 
  extreme 
  thinness. 
  The 
  true 
  interver- 
  

   tebral 
  foramina 
  pierced 
  through 
  the 
  middle 
  of 
  the 
  vertebra?, 
  and 
  are 
  

   small 
  transversely 
  oval 
  apertures 
  with 
  sharp 
  clean 
  margins 
  (fig. 
  1, 
  v), 
  

   such 
  as 
  could 
  only 
  have 
  been 
  left 
  by 
  a 
  thin 
  film 
  of 
  bone 
  having 
  been 
  

   removed. 
  The 
  junctions 
  of 
  the 
  vertebras- 
  appear 
  to 
  have 
  been 
  com- 
  

   plete, 
  so 
  that 
  no 
  aperture 
  existed 
  in 
  the 
  sutural 
  line 
  of 
  the 
  vertebrae. 
  

   The 
  width 
  of 
  the 
  cast 
  (fig. 
  2) 
  below 
  the 
  first 
  foramen 
  is 
  1*7 
  centim., 
  

   below 
  the 
  second 
  it 
  is 
  1*6 
  centim., 
  below 
  the 
  third 
  it 
  is 
  2 
  centim., 
  below 
  

   the 
  fourth 
  it 
  is 
  1-8 
  centim., 
  below 
  the 
  fifth 
  it 
  is 
  1*2 
  centim., 
  and 
  was 
  

   evidently 
  less 
  in 
  the 
  next 
  succeeding 
  vertebra. 
  These 
  foramina 
  lie 
  

   in 
  a 
  straight 
  line 
  (fig. 
  2)': 
  and 
  the 
  cast 
  expands 
  below 
  them 
  in 
  depth 
  as 
  

   though 
  it 
  sunk 
  into 
  the 
  bodies 
  of 
  the 
  vertebra? 
  ; 
  but 
  this 
  depression 
  

   is 
  very 
  small 
  in 
  amount, 
  as 
  is 
  evidenced 
  by 
  the 
  very 
  gentle 
  convexity 
  

   in 
  length 
  of 
  the 
  base 
  of 
  the 
  specimen 
  ; 
  but 
  superiorly 
  the 
  cast 
  ex- 
  

   pands 
  in 
  a 
  remarkable 
  way 
  in 
  a 
  convex 
  curve, 
  which, 
  however, 
  is 
  

   flattened 
  over 
  each 
  neural 
  arch 
  (fig. 
  2). 
  

  

  The 
  anterior 
  part 
  of 
  the 
  first 
  vertebra, 
  of 
  which 
  the 
  centrum 
  is 
  

   preserved, 
  is 
  broken 
  away, 
  so 
  that 
  its 
  depth 
  at 
  the 
  foramen 
  cannot 
  

   be 
  given 
  with 
  certainty: 
  it 
  was 
  probably 
  about 
  4-5 
  centim. 
  Over 
  

   the 
  second 
  foramen 
  (fig. 
  1, 
  3) 
  the 
  depth 
  is 
  7'5 
  centim., 
  over 
  the 
  third 
  

   (fig. 
  1, 
  1) 
  nearly 
  8-5 
  centim., 
  over 
  the 
  fourth 
  (fig. 
  1, 
  5) 
  6-7 
  centim., 
  over 
  

   the 
  fifth 
  (fig. 
  1, 
  6) 
  4 
  centim., 
  while 
  the 
  next 
  appears 
  to 
  be 
  diminishing 
  

   further. 
  Thus 
  this 
  neural 
  canal 
  is 
  distinguished 
  from 
  all 
  forms 
  

   hitherto 
  known 
  by 
  its 
  extraordinary 
  lateral 
  compression 
  relatively 
  

   to 
  height 
  in 
  the 
  middle 
  region. 
  

  

  The 
  foramina 
  appear 
  to 
  be 
  situate 
  at 
  about 
  the 
  middle 
  of 
  the 
  

   neural 
  canal 
  in 
  front, 
  below 
  the 
  middle 
  in 
  the 
  next 
  three 
  vertebrae, 
  

   and 
  above 
  the 
  middle 
  in 
  the 
  last 
  preserved. 
  

  

  The 
  first 
  foramen 
  does 
  not 
  differ 
  greatly 
  in 
  length 
  from 
  the 
  others 
  ; 
  

   it 
  is 
  under 
  2 
  centim. 
  long, 
  of 
  ovate 
  form, 
  and 
  1 
  centim. 
  deep. 
  Its 
  

   outlet 
  is 
  vertical 
  above 
  and 
  oblique 
  posteriorly. 
  The 
  second 
  foramen 
  

   is 
  deeper, 
  and 
  opens 
  obliquely 
  posteriorly; 
  the 
  third 
  foramen 
  is 
  

   narrower 
  than 
  the 
  first, 
  and 
  pointed 
  in 
  front 
  and 
  behind. 
  The 
  fourth 
  

   is 
  large, 
  and 
  the 
  fifth 
  small 
  and 
  narrow. 
  In 
  every 
  case 
  except 
  the 
  

   last 
  the 
  neural 
  canal 
  is 
  wider 
  above 
  the 
  foramen 
  than 
  below 
  it. 
  

  

  The 
  base 
  of 
  the 
  specimen 
  is 
  rounded 
  from 
  side 
  to 
  side 
  with 
  a 
  slight 
  

   longitudinal 
  median 
  groove 
  behind 
  (fig. 
  2), 
  and 
  with 
  an 
  expansion 
  or 
  

   swelling 
  in 
  the 
  region 
  of 
  the 
  sutures 
  between 
  the 
  vertebra?. 
  The 
  

   rounding 
  is 
  most 
  marked 
  in 
  the 
  middle 
  of 
  each 
  centrum 
  ; 
  and 
  in 
  front 
  

   there 
  is 
  a 
  slight 
  approach 
  to 
  flattening. 
  The 
  nutritive 
  foramina 
  

   (fig. 
  2,n) 
  are 
  well 
  seen 
  in 
  the 
  first 
  vertebra 
  preserved 
  ; 
  they 
  are 
  narrow, 
  

   1 
  centim. 
  long, 
  1 
  centim. 
  apart, 
  and 
  5 
  centim. 
  from 
  the 
  anterior 
  

   margin. 
  In 
  the 
  next 
  two 
  vertebra? 
  they 
  are 
  much 
  smaller 
  and 
  less 
  

  

  