﻿AND 
  AVES 
  OF 
  NORTH 
  AMERICA. 
  199 
  

  

  The 
  fang-like 
  supports 
  of 
  all 
  the 
  teeth 
  are 
  more 
  firmly 
  coossified 
  with 
  the 
  jaws, 
  than 
  is 
  usually 
  the 
  case 
  in 
  this 
  

   family, 
  and 
  most 
  of 
  them 
  contain 
  excavations 
  for 
  the 
  successional 
  teeth. 
  On 
  the 
  outer 
  superior 
  edge 
  of 
  the 
  lower 
  

   jaws 
  there 
  is 
  a 
  row 
  of 
  pits 
  round 
  or 
  oval 
  in 
  outline, 
  and 
  alternating 
  with 
  the 
  teeth. 
  In 
  most 
  instances 
  one 
  is 
  situated 
  

   outside 
  and 
  a 
  little 
  in 
  front 
  of 
  each 
  tooth, 
  and 
  those 
  in 
  the 
  anterior 
  portions 
  of 
  the 
  jaws 
  are 
  deeper 
  than 
  those 
  farther 
  

   back. 
  They 
  evidently 
  have 
  been 
  excavated 
  for 
  the 
  maxillary 
  teeth, 
  and 
  are 
  adapted 
  for 
  their 
  reception, 
  like 
  the 
  sim- 
  

   ilar 
  cavities 
  in 
  the 
  jaws 
  of 
  crocodiles. 
  Slight 
  depressions, 
  corresponding 
  to 
  these 
  in 
  position, 
  may 
  be 
  seen 
  in 
  the 
  jaws 
  

   of 
  some 
  of 
  the 
  larger 
  species 
  of 
  Mosasaurus, 
  and 
  the 
  unusual 
  depth 
  of 
  the 
  pits 
  in 
  the 
  present 
  specimen 
  is 
  probably 
  due 
  

   to 
  the 
  more 
  pointed 
  character 
  of 
  the 
  teeth. 
  

  

  Among 
  the 
  pieces 
  of 
  the 
  skull 
  preserved, 
  is 
  part 
  of 
  a 
  symmetrical 
  bone, 
  about 
  seven 
  inches 
  in 
  length, 
  which 
  

   formed 
  the 
  superior, 
  medial 
  portion 
  of 
  the 
  face 
  in 
  front 
  of 
  the 
  orbits. 
  Although 
  no 
  sutures 
  are 
  visible, 
  it 
  is 
  evidently 
  

   composed 
  of 
  the 
  nasal 
  bones, 
  and 
  portions 
  of 
  the 
  attached 
  premaxillary 
  and 
  frontal 
  bones. 
  Its 
  upper 
  surface 
  is 
  very 
  

   peculiar 
  in 
  form, 
  and 
  is 
  doubtless 
  quite 
  characteristic 
  of 
  the 
  species. 
  It 
  is 
  slightly 
  concave 
  in 
  front 
  where 
  broken 
  off, 
  

   flat 
  at 
  its 
  narrowest 
  part 
  between 
  the 
  nasal 
  openings, 
  convex 
  as 
  it 
  becomes 
  broader 
  a 
  little 
  farther 
  back, 
  next 
  flat 
  with 
  

   regular 
  beveled 
  edges 
  at 
  its 
  greatest 
  width 
  between 
  the 
  apertures, 
  and 
  finally 
  very 
  convex 
  as 
  it 
  again 
  expands 
  before 
  

   coalescing 
  with 
  the 
  medial 
  frontal. 
  This 
  fragment 
  indicates 
  that 
  the 
  nasal 
  bone 
  was 
  very 
  slender, 
  and 
  like 
  the 
  pre- 
  

   maxillary 
  undivided, 
  that 
  the 
  superior 
  nasal 
  openings 
  on 
  either 
  side 
  were 
  long 
  and 
  narrow, 
  and 
  that 
  the 
  central 
  line 
  

   of 
  the 
  face 
  immediately 
  behind 
  them 
  was 
  marked 
  by 
  a 
  low 
  rounded 
  ridge. 
  

  

  From 
  the 
  Lower 
  bed 
  of 
  Cretaceous 
  Green 
  Sand 
  at 
  Marlborough, 
  Monmouth 
  Co., 
  N. 
  J. 
  

   The 
  size 
  and 
  horizon 
  of 
  this 
  species 
  are 
  quite 
  similar 
  to 
  those 
  of 
  the 
  Clidastes 
  iguanavus. 
  

  

  MOSASAURUS 
  MIERSII, 
  Marsh. 
  

  

  Sill. 
  Amer. 
  Jour. 
  Sci. 
  Arts, 
  1869, 
  395. 
  

  

  The 
  following 
  description 
  is 
  derived 
  from 
  Marsh, 
  1. 
  c. 
  

  

  This 
  species 
  is 
  indicated 
  by 
  the 
  crown 
  of 
  a 
  single 
  tooth 
  which 
  was 
  found 
  in 
  the 
  lowest 
  marl 
  bed, 
  near 
  Horners- 
  

   town, 
  New 
  Jersey. 
  It 
  evidently 
  belonged 
  to 
  a 
  Mosasauroid 
  reptile 
  of 
  moderate 
  size, 
  but 
  appears 
  to 
  differ 
  from 
  the 
  

   teeth 
  of 
  any 
  yet 
  described, 
  in 
  being 
  more 
  pointed, 
  and 
  in 
  having 
  the 
  sides 
  very 
  deeply 
  facetted 
  or 
  grooved. 
  It 
  resem- 
  

   bles 
  strongly 
  the 
  teeth 
  of 
  Mosasaurus 
  copeanus, 
  but 
  is 
  more 
  compressed, 
  the 
  enamel 
  of 
  the 
  crown 
  more 
  corrugated, 
  

   the 
  cutting 
  edges 
  are 
  minutely 
  denticulated, 
  and 
  it 
  evidently 
  belonged 
  to 
  a 
  much 
  larger 
  animal. 
  The 
  crown 
  is 
  an 
  inch 
  • 
  

   and 
  five 
  lines 
  in 
  length, 
  and 
  eight 
  lines 
  in 
  antero-posterior 
  diameter 
  at 
  the 
  base. 
  The 
  facets 
  fade 
  away 
  before 
  reach- 
  

   ing 
  the 
  apex, 
  which 
  is 
  nearly 
  smooth. 
  

  

  This 
  tooth 
  is 
  apparently 
  too 
  large 
  for 
  either 
  of 
  the 
  species 
  of 
  Baptosaurus 
  described 
  below, 
  the 
  remains 
  of 
  which 
  

   were 
  found 
  in 
  the 
  same 
  immediate 
  vicinity, 
  but 
  it 
  may 
  possibly 
  belong 
  to 
  Liodon 
  Icevis, 
  the 
  teeth 
  of 
  which 
  are 
  

   unknown. 
  

  

  PLATECARPUS, 
  Cope. 
  

   Proc. 
  Bost. 
  Soc. 
  Nat. 
  Hist., 
  1869, 
  264. 
  

  

  This 
  genus 
  is 
  especially 
  characterized 
  by 
  the 
  peculiar 
  insertion 
  of 
  the 
  pterygoid 
  teeth. 
  

   Its 
  humerus 
  also 
  is 
  more 
  chelonian 
  than 
  that 
  of 
  Mosasaurus, 
  while 
  the 
  os 
  quadratum 
  pre- 
  

   sents 
  marked 
  differences. 
  These 
  peculiarities 
  have 
  been 
  pointed 
  out 
  by 
  Leidy, 
  who 
  refers 
  

   the 
  species 
  to 
  the 
  genus 
  Holcodus 
  of 
  Gibbes. 
  Now 
  this 
  genus, 
  Leidy 
  also 
  shows, 
  was 
  

   made 
  to 
  include, 
  also, 
  teeth 
  of 
  Hyposaurus, 
  but 
  the 
  name, 
  as 
  its 
  meaning 
  is 
  "grooved 
  

   tooth," 
  should 
  be 
  restricted 
  to 
  that 
  Mosasauroid 
  genus, 
  to 
  which 
  it 
  is 
  applicable. 
  

  

  