﻿80 
  COLLECTIONS 
  FROM 
  MELAN-ESIA. 
  

  

  being 
  only 
  14 
  millim. 
  in 
  length. 
  The 
  number 
  of 
  radiating 
  ridges 
  

   in 
  the 
  terminal 
  valves 
  varies 
  considerably 
  : 
  the 
  type 
  has 
  ten 
  in 
  

   the 
  front 
  one, 
  and 
  nine 
  in 
  the 
  posterior 
  ; 
  the 
  single 
  specimen 
  from 
  

   Port 
  Molle 
  has 
  the 
  same 
  number 
  in 
  front, 
  but 
  one 
  less 
  behind 
  ; 
  a 
  

   third 
  example 
  has 
  seventeen 
  anterior 
  and 
  sixteen 
  posterior 
  ones. 
  

   The 
  central 
  valves 
  are 
  arched, 
  but 
  exhibit 
  a 
  carina 
  at 
  the 
  vertex. 
  

   The 
  two 
  radiating 
  costae 
  are 
  sometimes 
  more 
  or 
  less 
  double 
  at 
  the 
  

   outer 
  ctrxemities. 
  The 
  longitudinal 
  thread-like 
  lira3 
  are 
  rather 
  

   granular 
  through 
  being 
  connected 
  with 
  the 
  still 
  finer 
  cross 
  raised 
  

   lines 
  ; 
  they 
  are 
  fairly 
  regular 
  upon 
  the 
  greater 
  part 
  of 
  the 
  surface, 
  

   but 
  down 
  the 
  centre 
  form 
  an 
  irregular 
  network, 
  not 
  unlike 
  the 
  

   reticulation 
  of 
  a 
  thimble. 
  The 
  interior 
  of 
  the 
  valves 
  is 
  for 
  the 
  most 
  

   part 
  pale 
  greenish 
  white, 
  but 
  towards 
  the 
  straight 
  posterior 
  margin 
  

   of 
  the 
  central 
  ones 
  a 
  buff 
  tint 
  prevails. 
  The 
  lamina 
  of 
  insertion 
  in 
  

   the 
  front 
  valve 
  is 
  divided 
  (a 
  single 
  specimen 
  only 
  has 
  been 
  examined) 
  

   by 
  eight 
  minute 
  notches 
  into 
  nine 
  subequal 
  squarely-cut 
  curved 
  

   teeth, 
  together 
  forming 
  a 
  festooned 
  semicircle 
  ; 
  from 
  each 
  slit 
  a 
  

   feeble 
  groove 
  runs 
  to 
  the 
  vertex 
  corresponding 
  to 
  an 
  external 
  rib. 
  

   The 
  central 
  valves 
  have 
  a 
  single 
  notch 
  on 
  each 
  side 
  immediately 
  

   beneath 
  the 
  termination 
  of 
  the 
  anterior 
  of 
  the 
  two 
  external 
  ridges. 
  

   The 
  lamina 
  is 
  turned 
  outward 
  at 
  this 
  point 
  and 
  also 
  at 
  the 
  other 
  

   rib, 
  forming 
  a 
  little 
  festoon. 
  The 
  last 
  plate 
  has 
  nine 
  notches, 
  one 
  

   correspoudiijg 
  to 
  each 
  rib, 
  with 
  a 
  single 
  (probably 
  unusual) 
  exception, 
  

   where 
  there 
  are 
  two. 
  The 
  vertex 
  in 
  this 
  valve 
  is 
  central. 
  The 
  

   scales 
  of 
  tlie 
  girdle 
  are 
  excessively 
  minute, 
  densely 
  crowded, 
  hardly 
  

   visible 
  under 
  an 
  ordinary 
  lens, 
  and 
  in 
  alternate 
  Hght 
  and 
  dark 
  patches. 
  

  

  111. 
  Chiton 
  (CallistocMton) 
  coppingeri. 
  (Plate 
  VI. 
  fig. 
  E.) 
  

  

  Shell 
  elongate, 
  greenish 
  white, 
  stained 
  with 
  a 
  dark 
  green 
  colour 
  

   along 
  each 
  side 
  near 
  the 
  girdle, 
  with 
  a 
  paler 
  indistinct 
  stripe 
  on 
  

   each 
  side 
  of 
  the 
  central 
  line, 
  the 
  apex 
  of 
  the 
  valves 
  being 
  somewhat 
  

   livid. 
  Central 
  valves 
  with 
  a 
  straight 
  posterior 
  margin, 
  arched, 
  with 
  

   only 
  the 
  faintest 
  indication 
  of 
  a 
  carina 
  at 
  the 
  vertex. 
  Lateral 
  areas 
  

   somewhat 
  raised, 
  with 
  two 
  radiating 
  rows 
  of 
  coarse 
  transverse 
  rugae, 
  

   of 
  which 
  the 
  hinder 
  or 
  marginal 
  are 
  the 
  largest. 
  The 
  surface 
  

   between 
  them 
  is 
  finely 
  granular. 
  Central 
  areas 
  convercd 
  with 
  a 
  

   more 
  or 
  less 
  criss-cross 
  granulation, 
  the 
  granules 
  at 
  the 
  centre 
  being 
  

   very 
  minnte, 
  and 
  gradually 
  increasing 
  in 
  size 
  towards 
  the 
  sides, 
  

   where 
  there 
  is 
  very 
  little 
  of 
  the 
  criss-cross 
  arrangement 
  seen 
  at 
  the 
  

   vertex, 
  but 
  rather 
  a 
  longitudinal 
  disposition 
  of 
  them. 
  The 
  front 
  

   valve 
  is 
  minutely 
  granulated 
  and 
  has 
  about 
  twenty 
  fine 
  radiating 
  

   ridges, 
  here 
  and 
  there 
  some 
  of 
  them 
  bifurcating 
  near 
  the 
  circumfer- 
  

   ence. 
  Posterior 
  valve 
  rather 
  large, 
  concave 
  behind 
  the 
  subcentral 
  

   mucro, 
  in 
  front 
  of 
  which 
  the 
  surface 
  is 
  sculptured 
  in 
  the 
  same 
  

   manner 
  as 
  the 
  front 
  of 
  the 
  central 
  valve, 
  as 
  is 
  usual 
  with 
  most, 
  if 
  

   not 
  all, 
  Chitons. 
  The 
  posterior 
  half 
  is 
  finely 
  grained 
  and 
  sparsely 
  

   covered 
  with 
  pustules 
  of 
  different 
  shapes 
  and 
  sizes, 
  the 
  coarsest 
  

   being 
  near 
  the 
  margin 
  and 
  the 
  smallest 
  near 
  the 
  centre. 
  The 
  in- 
  

   sertional 
  plates 
  are 
  thin, 
  with 
  twelve 
  slits 
  in 
  the 
  last, 
  at 
  unequal 
  

  

  