﻿102 
  PKOCKICDINGS 
  OF 
  THE 
  MALACOLOGICAL 
  SOCIETY. 
  

  

  cusp 
  long, 
  narrow, 
  twice 
  as 
  long 
  as 
  side 
  cusps; 
  side 
  cusps 
  sharp, 
  

   broad, 
  a 
  large 
  adherent 
  denticle 
  on 
  inside, 
  close 
  to 
  the 
  base, 
  point 
  

   turning 
  in, 
  3-5 
  well-marked 
  outer 
  denticles, 
  one 
  climbing 
  high 
  ; 
  

   knob 
  fairly 
  prominent. 
  

  

  aperta, 
  Blainv. 
  : 
  Hilo, 
  Hawaii. 
  The 
  tliree 
  great 
  cusps 
  are 
  nearly 
  

   eqival 
  in 
  length, 
  all 
  rather 
  broadly 
  triangular; 
  central 
  much 
  the 
  

   thickest, 
  with 
  root 
  carried 
  through 
  to 
  the 
  base, 
  which 
  it 
  causes 
  to 
  

   project 
  slightly; 
  side 
  cusps 
  with 
  a 
  prominent 
  blunt 
  denticle 
  low 
  

   down 
  and 
  close 
  to 
  the 
  cusps 
  ; 
  outside, 
  three 
  or 
  four 
  small 
  but 
  well- 
  

   marked 
  denticles, 
  the 
  innermost 
  very 
  small 
  and 
  climbing 
  ; 
  knob 
  blunt. 
  

   (Fig. 
  19.) 
  

  

  harpa, 
  Conr. 
  : 
  Sandwich 
  Is. 
  Ilather 
  a 
  large 
  radula 
  for 
  so 
  small 
  

   a 
  shell 
  ; 
  central 
  cusp 
  strong, 
  one-third 
  as 
  long 
  again 
  as 
  side 
  cusps 
  ; 
  side 
  

   cusps 
  rather 
  blunt 
  and 
  broad, 
  a 
  strong, 
  pointed, 
  slightly 
  incurved 
  

   denticle 
  rather 
  low 
  down 
  on 
  the 
  inside; 
  outside, 
  2-4 
  well-marked 
  

   denticles, 
  one 
  climbing, 
  Avhile 
  two 
  sometimes 
  combine 
  to 
  form 
  a 
  single 
  

   strong 
  denticle 
  ; 
  knob 
  well 
  marked 
  ; 
  base 
  slightly 
  waved 
  in 
  the 
  

   centre, 
  angles 
  of 
  base 
  sharp, 
  scarcely 
  produced 
  ; 
  laterals 
  remarkably 
  

   hooked 
  at 
  point. 
  

  

  One 
  cannot 
  help 
  being 
  struck 
  by 
  the 
  singular 
  general 
  likeness 
  of 
  

   the 
  radula 
  to 
  that 
  of 
  the 
  Dnipa 
  group. 
  

  

  mix, 
  lleeve 
  : 
  South 
  Pacitic. 
  Central 
  cusp 
  broad, 
  rather 
  short, 
  

   rapidly 
  tapering 
  to 
  a 
  sharp 
  point, 
  side 
  cusps 
  broad, 
  sliarply 
  pointed, 
  

   not 
  greatly 
  shorter 
  than 
  the 
  central, 
  peculiarly 
  denticled 
  high 
  up 
  on 
  

   the 
  inside, 
  denticle 
  slightly 
  angled 
  on 
  the 
  inside; 
  outside, 
  4-5 
  sharp, 
  

   well-marked 
  denticles, 
  the 
  innermost 
  climbing 
  high; 
  knob 
  

   prominent, 
  rather 
  narrow; 
  base 
  slightly 
  waved 
  in 
  the 
  centre, 
  

   slightly 
  angled 
  at 
  the 
  corners. 
  

  

  It 
  is 
  a 
  very 
  significant 
  fact 
  that 
  the 
  radulae 
  of 
  Thais 
  aperta, 
  

   Blainv., 
  harpa, 
  Conr., 
  and 
  mcx, 
  lleeve, 
  all 
  of 
  which 
  species 
  are 
  

   peculiar 
  to 
  the 
  Pacific 
  islands, 
  the 
  metropolis 
  of 
  Bnipa, 
  belong 
  

   distinctly 
  to 
  the 
  Driipa 
  type, 
  exhibiting 
  all 
  the 
  characteristics 
  in 
  

   which 
  that 
  type 
  differs 
  from 
  that 
  of 
  I'hais 
  proper, 
  under 
  which 
  group 
  

   these 
  three 
  species 
  have 
  always 
  been 
  hitherto 
  classified. 
  

  

  Rapana, 
  Schumacher. 
  

  

  R. 
  hulhosa, 
  Sol. 
  Central 
  and 
  side 
  cusps 
  very 
  broad 
  and 
  thick, 
  

   central 
  only 
  slightly 
  the 
  longer, 
  side 
  cusps 
  sharply 
  denticled 
  high 
  up 
  

   on 
  the 
  inside, 
  this 
  denticle 
  is 
  in 
  some 
  cases 
  so 
  tiny 
  as 
  to 
  be 
  scarcely 
  

   visible, 
  a 
  mere 
  nick 
  ; 
  no 
  exterior 
  denticles, 
  but 
  a 
  number 
  of 
  wrinkles 
  

   at 
  the 
  outer 
  base 
  of 
  the 
  side 
  cusps, 
  low 
  down, 
  not 
  in 
  the 
  plane 
  of 
  the 
  

   upper 
  margin 
  ; 
  no 
  knob 
  ; 
  sides 
  of 
  the 
  tooth 
  sloping 
  sharply 
  to 
  the 
  

   base, 
  which 
  is 
  simple, 
  bluntly 
  angled 
  at 
  each 
  side. 
  Troschel's 
  

   figure 
  needs 
  revision. 
  Specimens 
  from 
  Durban 
  and 
  Karachi 
  agree 
  

   completely. 
  (Fig. 
  29.) 
  

  

  R. 
  bezoar, 
  L. 
  Central 
  cusp 
  longer 
  and 
  narrower 
  than 
  in 
  hulbosa 
  ; 
  

   side 
  cusps 
  with 
  a 
  strong 
  sharp 
  denticle 
  high 
  up 
  ; 
  a 
  number 
  (about 
  

   half 
  a 
  dozen) 
  of 
  prominent 
  wrinkles 
  or 
  ridges 
  outside 
  the 
  side 
  cusps, 
  

   but 
  as 
  in 
  hulbosa, 
  below 
  the 
  upper 
  margin 
  of 
  the 
  tooth; 
  no 
  knob; 
  

  

  