﻿MOLLUSCA. 
  81 
  

  

  distances, 
  eleven 
  in 
  the 
  front 
  one, 
  and 
  one 
  on 
  each 
  side 
  of 
  the 
  inter- 
  

   mediate 
  valves. 
  The 
  interior 
  is 
  pale 
  blnish, 
  the 
  latter 
  valves 
  having 
  

   an 
  olive-brown 
  stain 
  radiating 
  from 
  the 
  vertex 
  behind 
  on 
  each 
  side, 
  

   and 
  the 
  two 
  terminal 
  valves 
  have 
  marks 
  of 
  the 
  same 
  colour 
  near 
  the 
  

   middle. 
  

  

  The 
  girdle 
  is 
  covered 
  with 
  altcrnateh" 
  pinkish 
  and 
  dark 
  greyish 
  

   patches 
  of 
  fine 
  oval 
  compressed 
  imbricating 
  scales, 
  of 
  which 
  those 
  

   towards 
  the 
  outer 
  margin 
  are 
  much 
  smaller 
  than 
  those 
  near 
  the 
  

   valves. 
  

  

  Length 
  without 
  girdle 
  21 
  millim. 
  ; 
  diameter 
  of 
  fifth 
  central 
  2)late 
  8. 
  

  

  Hab. 
  Port 
  Jackson 
  {Co2)phu/er). 
  

  

  This 
  species 
  is 
  closely 
  allied 
  to 
  C. 
  avtiquus, 
  but 
  is 
  diff'erently 
  and 
  

   more 
  finely 
  sculptured 
  and 
  the 
  scales 
  on 
  the 
  mantle 
  are 
  larger. 
  

  

  112. 
  Chiton 
  (Acanthopleura) 
  spiniger. 
  

  

  Chiton 
  spiniger, 
  Sowerhy, 
  Conch. 
  III. 
  fig. 
  08; 
  Reeve, 
  Conch. 
  Icon. 
  

  

  fig. 
  7o; 
  Gray, 
  1857, 
  Giiide 
  Moll. 
  Brit. 
  Mtis. 
  p. 
  184 
  (Maugeria)|; 
  Ball, 
  

  

  Bull. 
  U.S. 
  Nat. 
  Mus. 
  i. 
  p. 
  80 
  (Acanthopleura). 
  

   Chiton 
  granatus, 
  Reeve, 
  Condi. 
  Icon. 
  fig. 
  24. 
  

   Chiton 
  macgillivrayi, 
  A. 
  Adams, 
  Proc. 
  Zool. 
  Sac. 
  1855, 
  p. 
  120. 
  

   Acanthopleura 
  glareosa, 
  MS. 
  in 
  Mus. 
  Cuming. 
  

   Maugeria 
  owenii. 
  Gray, 
  (ruide 
  Moll. 
  p. 
  184. 
  

   ? 
  Chiton 
  borbouicus, 
  Deshayes, 
  Moll, 
  de 
  Reunion, 
  p. 
  37, 
  pi. 
  v. 
  figs. 
  

  

  12,13. 
  

   ? 
  Chiton 
  piceus, 
  Reeve 
  {non 
  Gmelin), 
  Conch. 
  Icon. 
  fig. 
  70. 
  

   = 
  Chiton 
  obesus, 
  Shidtleworth, 
  Bern. 
  Mittheil. 
  1853, 
  p. 
  79. 
  

   ? 
  Chiton 
  cunniughamii, 
  Reeve, 
  I. 
  c. 
  fig. 
  18. 
  

  

  Hcih. 
  Philippine 
  Islands 
  (Cuminr/) 
  ; 
  Port 
  Essington 
  (Jnl-es); 
  

   Port 
  Molle 
  and 
  Clairmont 
  and 
  Bird 
  Islands 
  (Cojipinr/er) 
  ; 
  Piji, 
  for 
  

   C. 
  macgillivrayi. 
  

  

  The 
  specific 
  difference, 
  if 
  it 
  exist, 
  between 
  the 
  West-Indian 
  

   C. 
  piceus 
  of 
  Gmelin 
  and 
  C. 
  spiniger 
  is 
  not 
  very 
  apparent. 
  On 
  close 
  

   comparison 
  I 
  find 
  that 
  the 
  central 
  valves 
  of 
  the 
  former 
  are 
  as 
  a 
  rule 
  

   more 
  peaked 
  posteriorly, 
  the 
  colour 
  within 
  is 
  bluish, 
  with 
  a 
  con- 
  

   spicuous 
  mark, 
  almost 
  black, 
  at 
  the 
  jugal 
  sinus. 
  On 
  separating 
  

   these 
  valves 
  the 
  greatest 
  diameter 
  is 
  found 
  to 
  exist 
  at 
  the 
  posterior 
  

   margin, 
  the 
  lamina3 
  of 
  insertion 
  narrowing 
  in 
  front. 
  On 
  the 
  con- 
  

   trary, 
  in 
  C. 
  spiniger 
  the 
  greatest 
  width 
  is 
  across 
  the 
  lamina; 
  anterior 
  

   to 
  the 
  lateral 
  notch. 
  There 
  appears 
  to 
  be 
  very 
  little 
  difference 
  in 
  

   the 
  insertion-teeth 
  of 
  the 
  first 
  and 
  last 
  valves 
  of 
  these 
  two 
  forms. 
  

  

  113. 
  Chiton 
  (Acanthopleura) 
  incanus. 
  

  

  Chiton 
  incanus, 
  Gould, 
  Proc. 
  Bost. 
  Soc. 
  Nat. 
  Hist. 
  1846, 
  vol. 
  ii. 
  

   p. 
  145 
  ; 
  ' 
  Otia,'' 
  pp. 
  6, 
  248 
  (Maugeria) 
  ; 
  Wilkes's 
  Explor. 
  Krped. 
  

   p. 
  315, 
  figs. 
  432, 
  432 
  «. 
  

  

  Hab. 
  New 
  South 
  Wales 
  (Gould); 
  Port 
  Jackson 
  (Coppinger) 
  ; 
  

   Stewart 
  Island, 
  New 
  Zealand 
  (C. 
  Traill, 
  Esq., 
  in 
  Brit. 
  Mus.). 
  

  

  Externally 
  this 
  species 
  bears 
  considerable 
  resemblance 
  to 
  0. 
  sjn- 
  

   niger, 
  both 
  as 
  regards 
  the 
  sculpture 
  of 
  the 
  valves 
  and 
  the 
  character 
  

  

  G 
  

  

  