﻿Report 
  of 
  the 
  State 
  Geologist. 
  359 
  

  

  position'to 
  the 
  lateral 
  occipitals 
  in 
  Coccosteus, 
  that 
  on 
  the 
  right 
  

   being 
  much 
  the 
  more 
  clearly 
  defined. 
  

  

  The 
  fragment 
  of 
  a 
  plate 
  lying 
  behind 
  the 
  median 
  occipital 
  and 
  

   at 
  the 
  right 
  post-lateral 
  extremity 
  (marked 
  sc), 
  I 
  take 
  to 
  be 
  a 
  

   scapular 
  or 
  supra 
  scapular. 
  Its 
  inner 
  extremity 
  bears 
  a 
  ball- 
  

   shaped 
  condyle 
  which 
  may 
  have 
  articulated 
  with 
  the 
  occipital 
  at 
  

   the 
  post-lateral 
  re-curvature 
  where 
  the 
  margin 
  of 
  that 
  plate 
  

   appears 
  to 
  be 
  entire. 
  

  

  Thus 
  far 
  the 
  structure 
  of 
  this 
  cr'anium 
  evinces 
  some 
  relation 
  to 
  

   Homosteus, 
  and 
  no 
  slight 
  agreement 
  with 
  Coccosteus; 
  still 
  there 
  

   are 
  some 
  conspicuous 
  points 
  of 
  difference 
  from 
  the 
  latter 
  genus, 
  

   notably 
  in 
  the 
  relation 
  of 
  the 
  ethmoid 
  {a. 
  e., 
  pt. 
  e.) 
  and 
  central 
  (c) 
  

   plates. 
  Whether 
  species 
  of 
  the 
  same 
  genus 
  may 
  vary 
  to 
  such 
  a 
  

   degree 
  in 
  the 
  structure, 
  is 
  a 
  point 
  which 
  is 
  referred 
  to 
  more 
  

   expert 
  fishermen. 
  

  

  The 
  denticulate 
  mandibles 
  lying 
  near 
  the 
  left 
  ante-lateral 
  

   margin 
  of 
  the 
  shield 
  will 
  have 
  a 
  definite 
  and 
  important 
  bearing 
  

   upon 
  this 
  subject. 
  

  

  Here 
  are 
  the 
  two 
  branches 
  of 
  the 
  lower 
  jaw 
  with 
  an 
  aspect 
  

   highly 
  similar 
  to 
  those 
  of 
  Dinicthys. 
  The 
  inner 
  of 
  the 
  two 
  

   ( 
  marked 
  man. 
  1.) 
  is 
  rather 
  the 
  more 
  complete, 
  though 
  its 
  anterior 
  

   termination 
  is 
  obscure 
  and 
  the 
  posterior 
  extremity 
  somewhat 
  

   indistinctly 
  expanded. 
  On 
  this 
  the 
  row 
  of 
  short 
  conical 
  denticu- 
  

   lations 
  situated 
  just 
  in 
  front 
  of 
  the 
  narrowest 
  part 
  of 
  the 
  organ 
  

   is 
  very 
  clear, 
  but 
  in 
  the 
  other 
  specimen 
  ( 
  man. 
  2. 
  ) 
  the 
  edge 
  is 
  

   broken 
  along 
  the 
  margin, 
  though 
  the 
  anterior 
  extremity 
  is 
  

   distinctly 
  defined 
  and 
  shows 
  three 
  relatively 
  large 
  cutting 
  points, 
  

   close 
  together 
  and 
  beveled 
  on 
  their 
  inner, 
  or 
  proximal 
  faces. 
  

   Though 
  this 
  mandible 
  appears 
  to 
  be 
  somewhat 
  shorter 
  than 
  the 
  

   other 
  I 
  believe 
  there 
  is 
  little 
  reason 
  to 
  doubt 
  the 
  correctness 
  of 
  

   the 
  interpretation 
  here 
  given 
  of 
  their 
  structure. 
  The 
  exterior 
  

   aspect 
  of 
  both 
  mandibles 
  is 
  shown. 
  

  

  There 
  seems 
  to 
  be 
  some 
  degree 
  of 
  uncertainty 
  as 
  to 
  the 
  

   structure 
  of 
  the 
  mandibles 
  in 
  Coccosteus 
  and 
  Homosteus. 
  Lydek- 
  

   ker's 
  restoration 
  of 
  Coccosteus 
  gives 
  a 
  curved 
  ramus 
  with 
  a 
  

   tubercled 
  surface 
  but 
  also 
  without 
  denticulations 
  ; 
  in 
  both 
  

   respects 
  unlike 
  the 
  specimen 
  under 
  consideration. 
  Zittel 
  speaks 
  

   of 
  the 
  mandibles 
  of 
  Coccosteus 
  as 
  elongate 
  bones 
  with 
  a 
  few 
  little 
  

   teeth, 
  and 
  von 
  Koenen 
  describes 
  a 
  ventro-lateral 
  rod-like 
  and 
  

  

  