﻿ASP1D0RHYNCHIDJE. 
  417 
  

  

  some 
  indications 
  of 
  a 
  short 
  supramaxilla 
  above 
  its 
  hinder 
  end. 
  The 
  

   premaxilla 
  is 
  also 
  much 
  elongated, 
  with 
  relatively 
  large 
  and 
  spaced 
  

   teeth 
  posteriorly 
  diminishing 
  to 
  minute 
  teeth 
  forwards 
  ; 
  it 
  is 
  fused 
  

   with 
  the 
  ethmoidal 
  region, 
  but 
  does 
  not 
  meet 
  its 
  fellow 
  of 
  the 
  

   opposite 
  side 
  in 
  front, 
  the 
  groove 
  between 
  this 
  pair 
  of 
  bones 
  being 
  

   continued 
  for 
  some 
  distance 
  along 
  the 
  base 
  of 
  the 
  rostrum. 
  Two 
  

   relatively 
  large 
  plates 
  of 
  the 
  suborbital 
  series 
  occupy 
  the 
  greater 
  

   portion 
  of 
  the 
  cheek 
  behind 
  the 
  orbit 
  ; 
  but 
  the 
  upper 
  plate, 
  as 
  also 
  

   sometimes 
  the 
  superior 
  end 
  of 
  the 
  lower 
  plate, 
  is 
  separated 
  from 
  

   the 
  preoperculum 
  by 
  a 
  third 
  element 
  which 
  is 
  truncated 
  above 
  and 
  

   acuminate 
  below. 
  There 
  are 
  also 
  small 
  cheek-plates 
  surrounding 
  the 
  

   narial 
  opening 
  immediately 
  in 
  advance 
  of 
  the 
  orbit 
  ; 
  but 
  the 
  circum- 
  

   orbitals 
  are 
  insignificant 
  and 
  apparently 
  do 
  not 
  form 
  a 
  continuous 
  

   ring. 
  The 
  sclerotic 
  is 
  ossified. 
  The 
  dentary 
  is 
  much 
  the 
  . 
  largest 
  

   element 
  in 
  the 
  mandible 
  and 
  bears 
  a 
  single 
  series 
  of 
  teeth 
  on 
  

   its 
  oral 
  border. 
  It 
  meets 
  its 
  fellow 
  of 
  the 
  opposite 
  side 
  at 
  the 
  

   symphysis, 
  and 
  articulates 
  in 
  front 
  with 
  an 
  azygous, 
  bilaterally- 
  

   symmetrical 
  presymphysial 
  bone. 
  Posteriorly 
  there 
  is 
  a 
  small 
  

   angular 
  plate 
  exposed 
  on 
  the 
  outer 
  face 
  of 
  the 
  ramus 
  ; 
  but 
  the 
  

   coronoid 
  has 
  not 
  hitherto 
  been 
  observed. 
  The 
  splenial 
  is 
  a 
  very 
  

   thin 
  lamina, 
  excavated 
  on 
  its 
  hinder 
  border 
  and 
  bearing 
  minute 
  

   teeth. 
  

  

  On 
  the 
  branchial 
  arches 
  the 
  calcified 
  supports 
  for 
  the 
  gill-filaments 
  

   are 
  always 
  conspicuous. 
  The 
  opercular 
  apparatus 
  is 
  complete, 
  and 
  

   there 
  is 
  a 
  long 
  series 
  of 
  branchiostegal 
  rays 
  ; 
  but 
  a 
  gular 
  plate 
  has 
  

   not 
  hitherto 
  been 
  observed. 
  

  

  The 
  vertebral 
  centra, 
  so 
  far 
  as 
  the 
  present 
  writer 
  has 
  observed 
  

   them, 
  are 
  always 
  in 
  the 
  form 
  of 
  delicate 
  rings, 
  each 
  bearing 
  its 
  own 
  

   arch. 
  The 
  ribs 
  are 
  very 
  short 
  and 
  thin. 
  In 
  the 
  abdominal 
  region 
  

   the 
  neural 
  spines 
  appear 
  to 
  be 
  separate 
  from 
  their 
  supporting 
  arches, 
  

   though 
  this 
  is 
  not 
  quite 
  certain 
  ; 
  in 
  the 
  caudal 
  region, 
  both 
  haemal 
  

   and 
  neural 
  spines 
  are 
  fused 
  with 
  their 
  arches, 
  and 
  the 
  latter 
  with 
  

   their 
  respective 
  centra. 
  As 
  might 
  be 
  expected 
  from 
  the 
  stout 
  pro- 
  

   portions 
  of 
  the 
  rays, 
  the 
  supports 
  of 
  the 
  dorsal 
  and 
  anal 
  fins 
  are 
  

   especially 
  robust 
  ; 
  and 
  they 
  are 
  shown 
  to 
  be 
  more 
  numerous 
  than 
  

   the 
  vertebral 
  segments 
  beneath 
  them. 
  

  

  The 
  scales 
  are 
  all 
  thick 
  and 
  rhombic, 
  strengthened 
  by 
  a 
  slight 
  

   internal 
  median 
  rib, 
  and 
  those 
  of 
  the 
  flank 
  united 
  by 
  a 
  large 
  

   peg-and-socket 
  articulation. 
  The 
  lateral 
  line 
  pierces 
  each 
  scale 
  it 
  

   traverses. 
  

  

  PART 
  III. 
  2 
  E 
  

  

  