﻿ANATOMY 
  AND 
  AFFINITIES 
  OF 
  T'dE 
  TUOOHIDJ]. 
  41 
  

  

  apparent. 
  Oil 
  the 
  other 
  hand, 
  in 
  those 
  species 
  belonging' 
  

   to 
  the 
  sub-genus 
  Call 
  io 
  stoma 
  the 
  riglit 
  and 
  left 
  cervicil 
  

   lobes 
  of 
  the 
  epipodium 
  are 
  perfectly 
  symmetrical, 
  their 
  

   margins 
  being 
  entire 
  and 
  free 
  from 
  pectinations. 
  According 
  

   to 
  Pelseneer 
  (36, 
  p. 
  46) 
  the 
  lobes 
  during 
  life 
  are 
  rolled., 
  up 
  

   on 
  themselves, 
  forming 
  channels 
  leading 
  into 
  the 
  mantle- 
  

   cavity, 
  and 
  serving 
  to 
  convey 
  water 
  into 
  and 
  out 
  of 
  it. 
  

  

  The 
  epipodium 
  is 
  furnished 
  on 
  either 
  side 
  with 
  three 
  or 
  

   more 
  tentacles, 
  which 
  can 
  be 
  extended 
  to 
  a 
  considerable 
  

   length. 
  They 
  are 
  highly 
  mus-jular, 
  and 
  present 
  a 
  great 
  

   similarity 
  in 
  structure 
  to 
  the 
  cephalic 
  tentacles, 
  and, 
  like 
  tliese, 
  

   are 
  covered 
  externally 
  by 
  numerous 
  fine 
  cilia 
  (fig. 
  7, 
  e^h 
  t.). 
  

   The 
  number 
  of 
  these 
  tentacles 
  is 
  very 
  constant 
  in 
  the 
  two 
  

   sub-genera; 
  in 
  Gribbula 
  there 
  are 
  always 
  three 
  on 
  each 
  

   side, 
  whilst 
  in 
  Calliostoma 
  either 
  four 
  or 
  five 
  are 
  present, 
  

   but 
  always 
  more 
  than 
  three. 
  At 
  the 
  base 
  of 
  these 
  tentacles 
  

   are 
  situated 
  some 
  small 
  appendices, 
  the 
  epipodial 
  papillas 
  

   (fig. 
  7, 
  ep. 
  p.), 
  which 
  either 
  vary 
  slightly 
  in 
  shape 
  and 
  

   occasionally 
  in 
  number 
  in 
  the 
  different 
  species, 
  or 
  may 
  be 
  

   entirely 
  absent, 
  as 
  in 
  T. 
  zizyphinus 
  and 
  T. 
  granulatus. 
  

   In 
  T. 
  cinerarias 
  they 
  are 
  club-shaped 
  structures; 
  in 
  

   T. 
  magus 
  they 
  show 
  a 
  tendency 
  to 
  branch, 
  whereas 
  in 
  

   T. 
  lineatus 
  they 
  are 
  wart-like 
  projections 
  at 
  the 
  base 
  of 
  

   the 
  tentacles. 
  They 
  are 
  undoubtedly 
  sensory 
  in 
  function, 
  

   probably 
  tactile, 
  and 
  are 
  innervated 
  by 
  the 
  nerve 
  going 
  to 
  

   the 
  epipodial 
  tentncle. 
  In 
  section 
  they 
  exhibit 
  a 
  slight 
  

   concave 
  depression 
  at 
  the 
  apex, 
  the 
  epithelium 
  lining 
  this 
  

   concavity 
  consisting 
  of 
  elongated 
  cells 
  occasionally 
  pigmented. 
  

  

  These 
  structures 
  have 
  been 
  regarded 
  as 
  accessory 
  eyes, 
  

   but 
  it 
  is 
  extremely 
  doubtful 
  if 
  they 
  are 
  other 
  than 
  tactile 
  

   organs. 
  In 
  addition 
  to 
  the 
  papilU\3 
  at 
  the 
  base 
  of 
  each 
  

   epipodial 
  tentacle 
  there 
  is 
  a 
  similar 
  organ 
  under 
  each 
  

   cei'vical 
  epipodium, 
  totally 
  unaccompanied 
  by 
  any 
  sensory 
  

   tentacle. 
  These 
  anterior 
  papilla) 
  exhibit 
  exactly 
  the 
  same 
  

   structure 
  as 
  those 
  previously 
  mentioned, 
  and 
  though 
  there 
  is 
  

   usually 
  one 
  present 
  on 
  either 
  side, 
  two 
  or 
  even 
  three 
  may 
  be 
  

   present 
  on 
  one 
  side 
  (generally 
  the 
  left) 
  and 
  one 
  on 
  the 
  other. 
  

  

  VOL. 
  48, 
  PART 
  1.- 
  — 
  NKW 
  SEIIIES. 
  4 
  

  

  