﻿82 
  COLLECXIOJrs 
  FROM 
  MELANESIA. 
  

  

  of 
  the 
  girdle. 
  On 
  parting 
  the 
  valves 
  a 
  feature 
  is 
  at 
  once 
  discovered 
  

   in 
  the 
  posterior 
  one 
  wliich 
  enables 
  us 
  to 
  distinguish 
  the 
  species 
  : 
  

   in 
  this 
  the 
  margin 
  is 
  very 
  much 
  thickened 
  within, 
  of 
  a 
  dark 
  brown 
  

   colour, 
  smooth, 
  flattened, 
  and 
  destitute 
  of 
  teeth, 
  whilst 
  in 
  C. 
  spiniger 
  

   the 
  latter 
  are 
  strongly 
  developed 
  and 
  coarsely 
  striated. 
  The 
  colour 
  

   of 
  the 
  interior 
  also 
  differs 
  : 
  C. 
  incaniis 
  is 
  stained 
  with 
  dark 
  brown, 
  

   the 
  centre 
  of 
  the 
  valves 
  exhibiting 
  a 
  large 
  defined 
  black-brown 
  mark 
  

   over 
  the 
  jugal 
  sinus, 
  the 
  lamina) 
  of 
  insertion 
  being 
  whitish. 
  The 
  

   central 
  valves 
  have 
  a 
  single, 
  very 
  small 
  slit 
  on 
  each 
  side, 
  and 
  the 
  

   front 
  one 
  has 
  about 
  nine 
  : 
  the 
  former, 
  with 
  the 
  exception 
  of 
  the 
  

   seventh, 
  are 
  broadest 
  across 
  the 
  posterior 
  margin, 
  as 
  is 
  also 
  the 
  case 
  

   in 
  the 
  closely 
  allied 
  AYest-Indian 
  C. 
  piceus, 
  whilst 
  in 
  0. 
  spiniger 
  

   the 
  greatest 
  diameter 
  is 
  across 
  the 
  laminae 
  of 
  insertion 
  in 
  front 
  of 
  

   the 
  notch. 
  The 
  jvigal 
  sinus 
  appears 
  to 
  be 
  rather 
  deeper 
  than 
  in 
  the 
  

   hitter 
  species. 
  The 
  specimens 
  from 
  IStewart 
  Island, 
  presented 
  to 
  

   the 
  British 
  Museum 
  by 
  Mr. 
  C. 
  Traill, 
  agree 
  in 
  all 
  respects 
  with 
  this 
  

   species 
  ; 
  the 
  form, 
  sculpture, 
  and 
  the 
  insertion-plates 
  are 
  quite 
  the 
  

   same. 
  

  

  114. 
  Chiton 
  (SchizocMton) 
  incisus. 
  

  

  Chiton 
  incisus, 
  Soiverby, 
  Pi'or. 
  Zvol. 
  Soc. 
  1841, 
  p. 
  Gl 
  ; 
  Reeve, 
  Conch. 
  

   Icon. 
  fig. 
  43. 
  

  

  Chiton 
  elougatus, 
  Reeve, 
  I. 
  c. 
  figs. 
  40 
  a, 
  b. 
  

  

  Schizochitou 
  incisus, 
  Gray, 
  Proc. 
  Zoo/. 
  Soc. 
  1847, 
  p. 
  169 
  ; 
  Shuttle- 
  

   worth, 
  Bern. 
  Mit.theil. 
  1853, 
  p. 
  G8 
  ; 
  H. 
  Sf 
  A. 
  Adams, 
  Genera 
  Rec. 
  

   Moll. 
  vol. 
  i. 
  p. 
  477, 
  pi. 
  54. 
  figs. 
  6, 
  G 
  a. 
  

  

  Hah. 
  Island 
  of 
  Zebu, 
  Philippines 
  {Cuming); 
  Raines 
  Island, 
  

   Torz'es 
  Straits 
  (Lice) 
  ; 
  Clairmont 
  and 
  Bird 
  Islands, 
  N.E. 
  Australia 
  

   (Coppinger). 
  

  

  The 
  mantle 
  is 
  thick, 
  of 
  a 
  somewhat 
  spongy 
  texture, 
  alternately 
  buff 
  

   and 
  dark 
  brown, 
  the 
  latter 
  colour 
  falling 
  opposite 
  the 
  middle 
  of 
  the 
  

   valves 
  and 
  forming 
  interrupted 
  irregular 
  narrow 
  stripes. 
  The 
  spines 
  

   upon 
  it 
  are 
  very 
  short, 
  scattered, 
  and 
  of 
  two 
  colours, 
  brown 
  and 
  

   white. 
  The 
  raised 
  ridges, 
  generally 
  six 
  in 
  number 
  on 
  the 
  terminal 
  

   valves, 
  but 
  sometimes 
  varying 
  to 
  seven 
  or 
  eight, 
  and 
  two 
  on 
  the 
  

   central 
  ones, 
  are 
  remarkable 
  in 
  being 
  studded 
  with 
  minute 
  blackish 
  

   beads. 
  The 
  longitudinal 
  fine 
  ridges 
  are 
  peculiarly 
  flat-topped, 
  

   those 
  on 
  the 
  central 
  areas 
  being 
  straight, 
  whilst 
  on 
  the 
  lateral 
  areas 
  

   and 
  the 
  front 
  valve 
  they 
  are 
  wavy 
  or 
  zigzag. 
  The 
  lamina 
  of 
  inser- 
  

   tion 
  in 
  the 
  front 
  valve 
  is 
  thin, 
  externally 
  striated, 
  with 
  six 
  notches 
  

   corresponding 
  to 
  the 
  radiating 
  costa?. 
  on 
  the 
  outer 
  surface. 
  In 
  the 
  

   central 
  valves 
  the 
  lamina 
  is 
  considerably 
  produced 
  in 
  front, 
  with 
  a 
  

   single 
  small 
  slit 
  on 
  each 
  side 
  : 
  in 
  the 
  last 
  valve 
  it 
  is 
  thickened 
  

   posteriorly, 
  interru])ted 
  in 
  the 
  middle 
  by 
  a 
  large 
  sinus, 
  is 
  coarsely 
  

   striated 
  on 
  the 
  o,utside, 
  and 
  is 
  slit 
  in 
  thiee 
  or 
  four 
  places. 
  The 
  in- 
  

   terior 
  of 
  the 
  valves 
  is 
  greenish, 
  staiiicd 
  with 
  brown 
  in 
  the 
  middle. 
  

  

  