﻿4 
  W. 
  H. 
  MOWER 
  ON 
  A 
  HALITHERIUM 
  

  

  the 
  orbit 
  is 
  completely 
  separated 
  from 
  the 
  nasal 
  fossa 
  b 
  v 
  a 
  stout 
  bony 
  

   wall 
  nearly 
  an 
  inch 
  in 
  thickness, 
  across 
  which 
  the 
  suture 
  between 
  

   the 
  frontal 
  (Fr.) 
  and 
  the 
  maxillary 
  (Mac.) 
  can 
  be 
  clearly 
  traced. 
  

   What 
  remains 
  of 
  the 
  anterior 
  root 
  of 
  the 
  zygoma 
  (•%.) 
  shows 
  that 
  

   this 
  process 
  must 
  have 
  been 
  considerably 
  more 
  massive 
  than 
  in 
  either 
  

   of 
  the 
  existing 
  species. 
  The 
  foramina 
  of 
  this 
  region 
  of 
  the 
  skull 
  

   correspond 
  generally 
  with 
  those 
  of 
  the 
  Manati. 
  Posteriorly 
  several 
  

   grooves 
  run 
  horizontally 
  forward 
  from 
  the 
  broken 
  part 
  of 
  the 
  skull 
  ; 
  

   one 
  of 
  these 
  (a) 
  conducts 
  the 
  optic 
  nerve 
  to 
  the 
  orbit. 
  Further 
  for- 
  

   ward, 
  in 
  the 
  suture 
  between 
  the 
  frontal 
  and 
  maxillary 
  bones 
  (at 
  b) 
  is 
  

   a 
  considerable-sized 
  foramen 
  (apparently 
  accidentally 
  enlarged 
  on 
  

   the 
  right 
  side) 
  for 
  the 
  passage 
  inwards 
  of 
  the 
  palatine 
  branches 
  of 
  

   the 
  second 
  division 
  of 
  the 
  fifth 
  nerve 
  In 
  front 
  of 
  the 
  anteorbital 
  

   foramen, 
  in 
  the 
  suture 
  between 
  the 
  maxilla 
  and 
  ascending 
  or 
  nasal 
  

   branch 
  of 
  the 
  preemaxilla, 
  is 
  a 
  foramen 
  (c). 
  which 
  transmits 
  the 
  

   branch 
  of 
  the 
  same 
  nerve 
  and 
  the 
  vessels 
  which 
  supply 
  the 
  horny 
  

   plate, 
  which 
  doubtless 
  existed 
  on 
  the 
  under 
  surface 
  of 
  the 
  rostrum. 
  

   This 
  canal 
  is 
  again 
  exposed 
  (at 
  d) 
  in 
  its 
  course 
  between 
  the 
  bones, 
  

   by 
  the 
  destruction 
  of 
  the 
  anterior 
  extremity 
  of 
  the 
  skull. 
  

  

  The 
  inferior 
  surface 
  (fig. 
  5, 
  two 
  thirds 
  natural 
  size) 
  shows 
  the 
  

   palate 
  and 
  sockets 
  of 
  the 
  molar 
  teeth. 
  The 
  former 
  is 
  elongated 
  and 
  

   narrow, 
  as 
  in 
  the 
  existing 
  Sirenians, 
  but 
  rather 
  broader 
  posteriorly 
  

   than 
  in 
  front. 
  Its 
  surface 
  is 
  quite 
  flat, 
  and 
  rounded 
  at 
  the 
  edges, 
  owing 
  

   to 
  attrition. 
  The 
  posterior 
  edge 
  is 
  concave 
  in 
  outline, 
  but 
  more 
  evenly 
  

   rounded 
  than 
  in 
  either 
  Dugong 
  or 
  Manati, 
  in 
  both 
  of 
  which 
  a 
  deep 
  

   V-shaped 
  notch 
  exists 
  in 
  the 
  middle 
  line, 
  entirely 
  wanting 
  in 
  the 
  

   present 
  fossil*. 
  The 
  suture 
  between 
  the 
  palatine 
  (PL.) 
  and 
  maxillary 
  

   bones 
  (Mx.) 
  is 
  very 
  distinctly 
  seen, 
  the 
  extent 
  of 
  the 
  former 
  being 
  

   much 
  the 
  same 
  as 
  in 
  the 
  modern 
  Sirenians. 
  Near 
  the 
  middle 
  line, 
  

   just 
  in 
  front 
  of 
  the 
  suture, 
  are 
  a 
  pair 
  of 
  foramina, 
  also 
  found 
  in 
  the 
  

   corresponding 
  situation 
  in 
  Manatus 
  ; 
  and 
  further 
  forward 
  are 
  several 
  

   irregular 
  foramina, 
  which 
  would 
  indicate 
  a 
  considerable 
  vascular 
  

   supply 
  to 
  this 
  part 
  of 
  the 
  palate, 
  as 
  in 
  the 
  recent 
  genera. 
  

  

  Dentition. 
  — 
  The 
  number 
  of 
  maxillary 
  teeth, 
  as 
  indicated 
  by 
  the 
  

   alveoli, 
  is 
  six 
  on 
  each 
  side, 
  all 
  placed 
  in 
  close 
  contact 
  with 
  each 
  

   other. 
  The 
  two 
  most 
  anterior 
  have 
  simple 
  rounded 
  alveoli 
  about 
  

   equal 
  in 
  size 
  (O0l7m. 
  in 
  diameter), 
  indicating 
  teeth 
  with 
  single 
  

   cylindrical 
  roots 
  as 
  in 
  the 
  Dugong, 
  but 
  differing 
  in 
  being 
  rounded 
  at 
  

   the 
  apex. 
  The 
  third 
  appears 
  to 
  have 
  had 
  two 
  roots, 
  outer 
  and 
  inner, 
  

   each 
  rounded 
  and 
  smaller 
  than 
  those 
  in 
  front. 
  The 
  three 
  following 
  

   teeth 
  resemble 
  each 
  other 
  in 
  form, 
  though 
  the 
  most 
  anterior 
  or 
  

   fourth 
  of 
  the 
  whole 
  series 
  is 
  rather 
  smaller 
  than 
  the 
  other 
  two. 
  

   They 
  have 
  three 
  roots 
  — 
  one 
  inner, 
  compressed 
  from 
  side 
  to 
  side, 
  and 
  

   two 
  supporting 
  the 
  outer 
  border, 
  each 
  compressed 
  from 
  before 
  back- 
  

   wards 
  exactly 
  as 
  in 
  the 
  Manati. 
  The 
  general 
  form 
  of 
  the 
  tooth 
  

   appears 
  wider 
  in 
  proportion 
  to 
  its 
  antero-posterior 
  diameter 
  than 
  in 
  

   that 
  genus 
  ; 
  but 
  this 
  is 
  perhaps 
  more 
  apparent 
  than 
  real, 
  as 
  the 
  

   minor 
  root, 
  as 
  in 
  the 
  Manati, 
  diverges 
  considerably 
  from 
  the 
  others, 
  

   so 
  that 
  the 
  deeper 
  the 
  section 
  the 
  wider 
  the 
  whole 
  base 
  of 
  the 
  tooth 
  

   * 
  The 
  notch 
  shown 
  in 
  the 
  figure 
  appears 
  to 
  be 
  due 
  to 
  a 
  fracture. 
  

  

  