﻿42 
  W. 
  J3. 
  EANDLES. 
  

  

  It 
  is 
  of 
  considerable 
  interest 
  to 
  note 
  that 
  in 
  T. 
  zizypliinus 
  

   and 
  T, 
  grannlatus 
  the 
  entire 
  absence 
  of 
  sensory 
  papillae 
  

   at 
  the 
  base 
  of 
  the 
  epipodial 
  tentacles 
  and 
  under 
  the 
  cervical 
  

   lobes 
  of 
  the 
  epipodium 
  is 
  correlated 
  with 
  the 
  perfect 
  

   symmetry 
  of 
  the 
  cervical 
  lobes 
  and 
  the 
  absence 
  of 
  an 
  

   appendix 
  on 
  the 
  right 
  ocular 
  peduncle. 
  In 
  the 
  following 
  

   species: 
  — 
  T. 
  striatus 
  and 
  T. 
  exasperatus, 
  — 
  which 
  are 
  

   included 
  in 
  the 
  sub-genus 
  Calliostoma, 
  — 
  the 
  cervical 
  lobes 
  

   are 
  symmetrical, 
  but 
  sensory 
  papilliB 
  are 
  present 
  under 
  these 
  

   lobes 
  and 
  also 
  at 
  the 
  base 
  of 
  the 
  tentacles, 
  and, 
  in 
  addition, 
  

   the 
  appendix 
  at 
  the 
  base 
  of 
  the 
  right 
  ocular 
  tentacle 
  occurs. 
  

   Moreover 
  the 
  specialised 
  glandular 
  area 
  on 
  the 
  dorsal 
  surface 
  

   of 
  the 
  foot 
  more 
  nearly 
  resembles 
  the 
  condition 
  seen 
  in 
  

   T. 
  magus 
  than 
  the 
  V-shaped 
  area 
  in 
  T. 
  grannlatus. 
  

  

  The 
  operculum 
  is 
  a 
  circular, 
  multispiral, 
  chitinons 
  disc 
  

   with 
  a 
  central 
  nucleus; 
  the 
  whorls 
  overlap 
  each 
  other 
  and 
  are 
  

   marked 
  in 
  a 
  radial 
  direction 
  by 
  numerous 
  strige 
  indicating 
  

   lines 
  of 
  growth. 
  It 
  differs 
  slightly 
  in 
  the 
  two 
  sub-genera, 
  

   both 
  in 
  colour 
  and 
  also 
  in 
  the 
  number 
  of 
  whorls 
  com- 
  

   posing 
  it. 
  In 
  Gibbula 
  it 
  is 
  dark 
  brown, 
  and 
  the 
  whorls, 
  

   which 
  are 
  fewer 
  in 
  number 
  than 
  in 
  Calliostoma, 
  range 
  

   from 
  six 
  and 
  a 
  half 
  to 
  seven 
  in 
  adult 
  specimens 
  of 
  T. 
  magus 
  

   (fig. 
  10), 
  to 
  ten 
  or 
  twelve 
  whorls 
  in 
  T. 
  umbilicatus 
  and 
  

   T. 
  lineatus. 
  The 
  lines 
  of 
  growth 
  are 
  very 
  distinct, 
  and 
  

   on 
  the 
  under 
  side 
  of 
  the 
  operculum 
  a 
  bean-shaped 
  scar 
  

   (fig. 
  10, 
  m. 
  his.), 
  situated 
  eccentrically, 
  marks 
  the 
  area 
  of 
  

   attachment 
  of 
  the 
  operculum 
  to 
  the 
  columella 
  muscle 
  and 
  

   opercular 
  lobe 
  of 
  the 
  foot. 
  In 
  Calliostoma 
  the 
  operculum 
  

   is 
  of 
  a 
  light 
  yellow 
  colour, 
  the 
  volutions 
  are 
  more 
  numerous, 
  

   ranging 
  from 
  thirteen 
  to 
  fourteen 
  in 
  T. 
  striatus, 
  

   T. 
  exasperatus, 
  and 
  T. 
  granulatus 
  to 
  as 
  many 
  as 
  

   fifteen 
  or 
  sixteen 
  in 
  T. 
  zizyphinis 
  (fig. 
  11). 
  In 
  this 
  

   latter 
  species 
  the 
  lines 
  of 
  growth 
  are 
  very 
  close 
  together, 
  and 
  

   are 
  more 
  distinct 
  on 
  the 
  outer 
  half 
  of 
  the 
  whorl. 
  The 
  area 
  of 
  

   the 
  muscle 
  attachment 
  is 
  more 
  or 
  less 
  triangular 
  in 
  shape. 
  

  

  The 
  Pallial 
  Complex. 
  — 
  The 
  mantle 
  is 
  thin 
  walled, 
  

   with 
  the 
  free 
  edge 
  slightly 
  thickened 
  and 
  occasionally 
  plicated. 
  

  

  