﻿MOLLtJSCA. 
  109 
  

  

  twice 
  as 
  many, 
  and 
  produce 
  a 
  denticulate 
  margin 
  to 
  the 
  valves. 
  

   Interior 
  slightly 
  iridescent. 
  Umbones 
  small, 
  glossy, 
  not 
  radiately 
  

   sculptured 
  like 
  the 
  rest 
  of 
  the 
  shell. 
  Length 
  6 
  millim., 
  height 
  3-|, 
  

   diam. 
  3. 
  

  

  Hah. 
  Dundas 
  Straits. 
  

  

  This 
  is 
  a 
  very 
  prettily 
  sculptured 
  species, 
  approaching, 
  as 
  regards 
  

   outline, 
  M. 
  varicosa. 
  It 
  is, 
  however, 
  quite 
  distinguishable 
  by 
  the 
  

   greater 
  coarseness 
  and 
  subgranular 
  character 
  of 
  the 
  radiating 
  ante- 
  

   rior 
  and 
  posterior 
  ridges. 
  

  

  The 
  single 
  specimen 
  described 
  above 
  may 
  not 
  be 
  full-grown 
  ; 
  but 
  

   I 
  conjecture 
  it 
  never 
  attains 
  a 
  much 
  larger 
  size. 
  

  

  53. 
  Modiolaria 
  varicosa. 
  (Plate 
  VII. 
  figs. 
  M, 
  M 
  1.) 
  

   Goidd, 
  Proc. 
  Bost. 
  Soc. 
  Nat. 
  Hist. 
  1861, 
  vol. 
  viii. 
  ; 
  Otia 
  Conch, 
  p. 
  176. 
  

  

  Hah. 
  Port 
  Jackson 
  ( 
  Coj929iHfjrer) 
  ; 
  Sydney 
  (&'o?tZ(:^). 
  

  

  This 
  pretty 
  little 
  species 
  was 
  figured 
  by 
  Reeve 
  (Conch. 
  Icon. 
  fig. 
  83) 
  

   as 
  the 
  young 
  of 
  Modiola 
  str'igata, 
  Hanley 
  ; 
  and 
  this 
  must 
  have 
  in- 
  

   duced 
  Gould 
  to 
  observe 
  that 
  it 
  '' 
  is 
  marked 
  like 
  " 
  that 
  species, 
  for 
  

   in 
  reality 
  there 
  is 
  very 
  little 
  resemblance 
  in 
  the 
  painting 
  of 
  the 
  two 
  

   shells. 
  The 
  radiating 
  sculpture 
  is 
  faintly 
  indicated 
  in 
  the 
  above 
  

   figure 
  by 
  means 
  of 
  scratched 
  lines, 
  but 
  these 
  are 
  only 
  noticeable 
  

   under 
  a 
  lens. 
  

  

  54. 
  Lithodomus 
  teres. 
  

  

  Modiola 
  teres, 
  Philipjn, 
  Abbild. 
  vol. 
  ii. 
  p. 
  148, 
  pi. 
  1. 
  fig. 
  3. 
  

   Lithodomus 
  teres, 
  Peeve, 
  Conch. 
  Icon. 
  fig. 
  13. 
  

  

  Hab. 
  Pacific 
  Ocean 
  (Phil.): 
  Philippine 
  Islands 
  (Cuming); 
  Port 
  

   Deuison, 
  Queensland 
  (Coppinger). 
  

  

  The 
  anterior 
  perpendicular 
  strise 
  are 
  rather 
  coarse 
  in 
  this 
  species 
  ; 
  

   the 
  raised 
  interstices 
  between 
  them 
  are 
  very 
  conspicuous 
  at 
  the 
  

   margin, 
  and 
  gradually 
  become 
  finer 
  as 
  they 
  ascend 
  the 
  valves, 
  some- 
  

   times 
  furcating 
  at 
  one 
  or 
  more 
  of 
  the 
  concentric 
  lines 
  of 
  growth. 
  

   The 
  interior 
  is 
  pinkish 
  or 
  bluish, 
  and 
  more 
  or 
  less 
  iridescent. 
  

  

  55. 
  Area 
  navicularis. 
  

  

  Bruguiere; 
  P/nlijjpi, 
  Abbild. 
  vol. 
  ii. 
  pi. 
  3. 
  fig. 
  2; 
  Peeve, 
  Conch. 
  Icon. 
  

  

  fig. 
  70 
  ; 
  Wood, 
  Index 
  Test. 
  pi. 
  9. 
  fig. 
  5. 
  

   Var. 
  =Arca 
  linter, 
  Jonas, 
  Philippi, 
  I. 
  c. 
  fig. 
  1. 
  

   Var.=Arca 
  subquadrangiila, 
  Dimker, 
  Philippi, 
  I. 
  c. 
  fig. 
  3. 
  

   Var. 
  = 
  Area 
  cvmiingii, 
  Dunker 
  (MS. 
  in 
  coll. 
  Cuming) 
  ; 
  Adams, 
  Genera 
  

  

  Moll. 
  ii. 
  p. 
  533. 
  

  

  Hah. 
  Port 
  MoUe, 
  Queensland 
  (Copjjzn^er) 
  ; 
  Port 
  Phillip, 
  China, 
  

   Cape 
  Capricorn, 
  Amboina 
  (Brit. 
  Miis.). 
  

  

  The 
  varieties 
  respectively 
  called 
  A. 
  linter 
  and 
  A. 
  suhquadrangula 
  

   are 
  distinguished 
  only 
  by 
  very 
  variable 
  characters, 
  such 
  as 
  form 
  and 
  

   the 
  amount 
  of 
  ligament, 
  which 
  in 
  this 
  group 
  of 
  Arks 
  are 
  of 
  little 
  

   value. 
  

  

  