﻿394 
  PEOCEEDINGS 
  OF 
  THE 
  GEOLOGICAL 
  SOCIETY. 
  [May 
  25, 
  

  

  the 
  triangle 
  being 
  directed 
  backwards. 
  The 
  hinder 
  third 
  of 
  the 
  in- 
  

   ferior 
  surface, 
  rough 
  and 
  irregular, 
  doubtless 
  gave 
  attachment 
  to 
  the 
  

   palatine 
  bones. 
  It 
  is 
  separated 
  by 
  a 
  curved 
  shoulder-lilie 
  projection, 
  

   which 
  fades 
  away 
  anteriorly 
  into 
  a 
  slight 
  linear 
  depression, 
  from 
  the 
  

   smooth 
  lateral 
  surface 
  of 
  the 
  rostrum. 
  

  

  The 
  upper 
  face 
  exhibits 
  a 
  central 
  area, 
  about 
  1 
  inch 
  wide, 
  and 
  

   bounded 
  by 
  the 
  well-defined 
  parallel 
  grooves, 
  which 
  end 
  posteriorly 
  

   in 
  short 
  covered 
  ways. 
  These 
  terminate 
  in 
  the 
  front 
  walls 
  of 
  two 
  

   canals 
  (ad), 
  which 
  open 
  above 
  by 
  somewhat 
  funnel-shaped 
  rounded 
  

   apertures, 
  looking 
  a 
  little 
  backwards 
  as 
  well 
  as 
  upwards. 
  The 
  canals 
  

   lead 
  from 
  these 
  apertures, 
  at 
  first 
  downwards 
  and 
  a 
  little 
  forwards, 
  

   and 
  then 
  turn 
  sharply 
  backwards, 
  to 
  become 
  much 
  wider, 
  and 
  ter- 
  

   minate 
  on 
  the 
  posterior 
  face 
  of 
  the 
  specimen. 
  Between 
  these 
  canals 
  

   the 
  same 
  face 
  exhibits 
  a 
  large 
  and 
  deep 
  fossa. 
  

  

  About 
  2| 
  inches 
  in 
  front 
  of 
  the 
  upper 
  apertures 
  of 
  the 
  canals 
  the 
  

   " 
  central 
  area" 
  exhibits 
  the 
  commencement 
  of 
  a 
  slit 
  (6), 
  which 
  deepens 
  

   as 
  it 
  passes 
  backwards, 
  and 
  becomes 
  lost 
  in 
  an 
  irregular 
  fossa. 
  The 
  

   slit 
  is 
  not 
  perfectly 
  central 
  or 
  symmetrical. 
  The 
  left 
  face 
  of 
  the 
  

   specimen 
  is 
  more 
  complete 
  than 
  the 
  right. 
  It 
  exhibits 
  the 
  two 
  

   grooves, 
  ending 
  behind 
  in 
  canals 
  already 
  mentioned, 
  and 
  the 
  third 
  

   slighter 
  groove, 
  which 
  is 
  continuous 
  with 
  the 
  curved 
  flange, 
  or 
  

   shoulder, 
  against 
  which 
  the 
  palatine 
  bone 
  fitted. 
  

  

  On 
  the 
  right 
  side 
  a 
  good 
  deal 
  of 
  the 
  bone 
  is 
  broken 
  away 
  from 
  

   the 
  posterior 
  half 
  of 
  its 
  lateral 
  face, 
  and 
  the 
  canal 
  under 
  the 
  ridge 
  

   is 
  laid 
  open. 
  About 
  three-quarters 
  of 
  an 
  inch 
  below 
  it 
  there 
  is 
  

   another 
  canal 
  of 
  the 
  same 
  size, 
  and 
  running 
  parallel 
  into 
  the 
  fore- 
  

   going, 
  which 
  is 
  filled 
  with 
  hard 
  ferruginous 
  matrix. 
  It 
  opens 
  

   posteriorly 
  on 
  the 
  palatine 
  flange. 
  

  

  The 
  ends 
  of 
  two 
  canals, 
  which 
  would 
  seem 
  to 
  be 
  distinct 
  from 
  

   either 
  of 
  these, 
  are 
  seen 
  in 
  the 
  middle 
  of 
  the 
  fractured 
  distal 
  end 
  

   of 
  the 
  specimen 
  (fig. 
  D). 
  

  

  It 
  is 
  probable 
  (as 
  Duvernoy 
  has 
  already 
  pointed 
  out) 
  that 
  the 
  

   " 
  central 
  area" 
  indicates 
  the 
  upper 
  extent 
  of 
  the 
  vomer, 
  the 
  only 
  

   remains 
  of 
  its 
  primitive 
  trough-like 
  cavity 
  being 
  the 
  median 
  slit 
  

   above 
  and 
  the 
  large 
  fossa 
  behind. 
  Into 
  the 
  latter 
  the 
  remains 
  of 
  

   the 
  cartilaginous 
  ethmoidal 
  septum 
  doubtless 
  fitted. 
  

  

  The 
  lateral 
  ridges, 
  with 
  the 
  grooves, 
  which 
  continue 
  their 
  direction 
  

   downwards 
  and 
  forwards, 
  define 
  the 
  outer 
  and 
  lower 
  margins 
  of 
  the 
  

   premaxillae 
  in 
  which 
  the 
  curved 
  canals 
  are 
  situated 
  ; 
  and 
  between 
  

   these 
  ridges 
  and 
  grooves, 
  the 
  flange, 
  and 
  the 
  sulcus 
  into 
  which 
  it 
  

   passes, 
  the 
  surface 
  of 
  the 
  rostrum 
  probably 
  appertains 
  to 
  the 
  

   maxilla. 
  

  

  Rather 
  more 
  than 
  the 
  anterior 
  third 
  of 
  the 
  under 
  surface 
  of 
  the 
  

   specimen 
  has 
  the 
  form 
  of 
  a 
  smooth 
  area, 
  narrower 
  behind 
  than 
  in 
  

   front, 
  which 
  probably 
  belongs 
  partly 
  to 
  the 
  vomer 
  and 
  partly 
  to 
  the 
  

   maxillee. 
  

  

  It 
  may 
  conduce 
  to 
  clearness 
  of 
  conception 
  of 
  the 
  relations 
  of 
  the 
  

   solid-beaked 
  Dolphins 
  of 
  the 
  Crag 
  with 
  the 
  allied 
  species 
  of 
  Cetacea, 
  

   if 
  I 
  now 
  arrange 
  the 
  different 
  known 
  forms 
  in 
  a 
  table, 
  parallel 
  with 
  

   the 
  genera 
  into 
  which 
  they 
  appear 
  most 
  conveniently 
  to 
  fall. 
  

  

  