﻿VEETEBEATES. 
  209 
  

  

  imperfect 
  state 
  of 
  preservation. 
  A 
  nearly 
  perfect 
  mandibular 
  tooth, 
  

   save 
  for 
  the 
  mutilation 
  of 
  the 
  outer 
  posterior 
  angle, 
  from 
  the 
  Lower 
  

   Burlington 
  limestone, 
  may 
  not 
  be 
  distinguishable 
  from 
  less 
  perfect 
  

   specimens 
  from 
  the 
  main 
  fish-bed 
  of 
  the 
  Upper 
  Burlington 
  in 
  which 
  

   occur 
  the 
  maxillary 
  teeth 
  described. 
  The 
  almost 
  quadrangular 
  shape 
  

   of 
  the 
  form 
  and 
  its 
  proportionately 
  narrower 
  transverse 
  diameter 
  are 
  

   the 
  only 
  apparent 
  characters 
  inconsistent 
  with 
  their 
  association 
  with 
  

   the 
  typical 
  example 
  of 
  the 
  supposed 
  maxillary 
  form 
  above 
  noticed. 
  

   The 
  same 
  horizon 
  in 
  the 
  Upper 
  Burlington 
  limestone 
  at 
  Quincy, 
  

   however, 
  has 
  afforded 
  Professor 
  Worthen 
  a 
  unique 
  specimen 
  of 
  a 
  

   tooth 
  referable 
  to 
  the 
  same 
  form, 
  which 
  is 
  distinguished 
  by 
  its 
  nar- 
  

   row 
  lateral 
  diameter 
  and 
  more 
  quadrangular 
  outline, 
  which, 
  together 
  

   with 
  the 
  course 
  of 
  the 
  anterior 
  and 
  posterior 
  margins, 
  strikingly 
  re- 
  

   semble 
  the 
  opposed 
  form 
  mentioned 
  above 
  ; 
  its 
  transversely 
  depressed 
  

   coronal 
  surface, 
  however, 
  clearly 
  discloses 
  its 
  homological 
  identity 
  

   with 
  the 
  supposed 
  maxillary 
  form. 
  Greater 
  or 
  less 
  variability 
  in 
  the 
  

   proportions 
  of 
  these 
  teeth 
  may 
  be 
  readily 
  anticipated, 
  and 
  the 
  latter 
  

   example 
  may 
  be 
  merely 
  an 
  unusually 
  elongate 
  tooth 
  of 
  the 
  same 
  

   species 
  as 
  that 
  regarded 
  as 
  the 
  type 
  of 
  the 
  species, 
  first 
  described 
  

   above. 
  However, 
  should 
  this 
  supposition 
  prove 
  to 
  be 
  erroneous, 
  the 
  

   last 
  mentioned 
  tooth 
  would 
  then 
  be 
  a 
  unique 
  representative 
  of 
  a 
  

   distinct 
  species, 
  while 
  the 
  narrow 
  tooth 
  would 
  probably 
  be 
  identi- 
  

   fiable 
  with 
  the 
  species 
  to 
  which 
  the 
  maxillary 
  teeth 
  described 
  above 
  

   belong. 
  

  

  The 
  forms 
  described 
  differ 
  in 
  so 
  marked 
  a 
  manner 
  from 
  those 
  of 
  

   the 
  previously 
  described 
  species, 
  Psammodus 
  Springeri, 
  P. 
  tumidus, 
  

   P. 
  turgidus, 
  as 
  not 
  to 
  require 
  special 
  review 
  of 
  their 
  distinctive 
  fea- 
  

   tures. 
  The 
  maxillary 
  form 
  offers 
  a 
  typical 
  example 
  of 
  the 
  genus, 
  

   and 
  which 
  strongly 
  resemble^ 
  individuals 
  of 
  P. 
  porosus, 
  Agass. 
  The 
  

   specific 
  name 
  is 
  given 
  in 
  honor 
  of 
  Mr. 
  James 
  Love, 
  of 
  Burlington, 
  

   to 
  whom 
  we 
  are 
  indebted 
  for 
  many 
  favors. 
  

  

  Geological 
  position 
  and 
  localities 
  : 
  Lower 
  and 
  Upper 
  Burlington 
  

   limestone; 
  Burlington, 
  Iowa, 
  and 
  Quincy, 
  Illinois. 
  

  

  Psammodus 
  glyptus, 
  St. 
  J. 
  and 
  W. 
  

  

  PL 
  XIV. 
  Fig. 
  5,6. 
  

  

  There 
  are 
  two 
  imperfect 
  specimens 
  of 
  large-size 
  teeth 
  in 
  the 
  col- 
  

   lections 
  representing 
  opposed 
  forms 
  of 
  the 
  upper 
  and 
  lower 
  jaws, 
  

   which 
  are 
  distinguished 
  by 
  the 
  very 
  slight 
  longitudinal 
  convexity 
  and 
  

   by 
  the 
  following 
  characteristics 
  respectively: 
  The 
  form 
  probably 
  

  

  —14 
  

  

  