﻿38 
  W. 
  B. 
  WANDT.ES. 
  

  

  Trochns 
  at 
  any 
  rnte 
  it 
  lias 
  niidoubtetlly 
  notliing 
  whatever 
  to 
  

   do 
  with 
  the 
  genitalia; 
  at 
  least 
  it 
  is 
  not 
  of 
  the 
  natni'e 
  of 
  a 
  

   penis, 
  because 
  when 
  present 
  it 
  is 
  found 
  in 
  both 
  male 
  and 
  

   female. 
  Besides, 
  it 
  is 
  a 
  solid 
  oi-gan 
  and 
  exhibits 
  no 
  trace 
  of 
  

   canal 
  or 
  groove 
  which 
  might 
  serve 
  for 
  the 
  transmission 
  of 
  

   sperms, 
  and 
  were 
  it 
  of 
  this 
  natui-e 
  we 
  should 
  expect 
  to 
  find 
  it 
  

   in 
  all 
  species, 
  and 
  not, 
  as 
  is 
  actnally 
  the 
  case, 
  ]iresent 
  in 
  some 
  

   and 
  absent 
  in 
  others. 
  Those 
  species 
  in 
  which 
  it 
  occurs 
  ai'e 
  

   mainly 
  littoral 
  forms, 
  and 
  there 
  appears 
  to 
  be 
  some 
  correlation 
  

   between 
  its 
  pi-eseuee 
  and 
  the 
  existence 
  of 
  a 
  certain 
  asynimeti'y 
  

   that 
  occurs 
  in 
  the 
  epipodial 
  lobes 
  of 
  these. 
  

  

  The 
  foot 
  is 
  a 
  large 
  muscular 
  organ, 
  ca]ial)le 
  of 
  great 
  

   extension; 
  it 
  is 
  beset 
  on 
  its 
  lateral 
  sui-faces 
  with 
  numerous 
  

   papilla3, 
  giving 
  it 
  a 
  rugose 
  appearance. 
  The 
  anterior 
  margin 
  

   pi-esents 
  in 
  some 
  species, 
  T. 
  granulatus, 
  etc. 
  (fig. 
  6), 
  a 
  

   large 
  tranverse 
  groove 
  separating 
  the 
  sole 
  from 
  the 
  upper 
  

   part 
  of 
  the 
  foot. 
  A 
  similai" 
  groove 
  occurs 
  in 
  PI 
  eurotomari 
  a 
  

   and 
  many 
  other 
  Gasteropods 
  ; 
  it 
  is 
  evidently 
  of 
  importance, 
  

   though 
  its 
  function 
  is 
  somewhat 
  enigmatical. 
  In 
  the 
  Trochidae 
  

   it 
  is 
  present 
  only 
  in 
  those 
  species 
  belonging 
  to 
  the 
  sub-genus 
  

   Calliostoma, 
  and 
  is 
  not 
  represented 
  in 
  any 
  of 
  the 
  Gibbulee 
  

   which 
  I 
  have 
  had 
  the 
  opportunity 
  of 
  examining. 
  When 
  

   present 
  this 
  groove 
  leads 
  into 
  a 
  lai-ge 
  tubular 
  pedal 
  gland 
  

   (fig. 
  6, 
  p. 
  gh), 
  which 
  extends 
  some 
  distance 
  into 
  the 
  anterior 
  

   portion 
  of 
  the 
  foot 
  ; 
  the 
  gland 
  is 
  composed 
  of 
  large 
  deeply 
  

   staining 
  cells, 
  containing 
  granular 
  protoplasm 
  and 
  rather 
  

   small 
  nuclei. 
  The 
  canal 
  of 
  the 
  gland 
  is 
  lincnl 
  with 
  ciliated 
  

   epithelium. 
  Houssay 
  has 
  described 
  a 
  similar, 
  though 
  slightly 
  

   more 
  complex 
  gland 
  in 
  Trivia 
  Europsea 
  (23, 
  pp. 
  272 
  — 
  275, 
  

   pi. 
  xiv, 
  \\^. 
  2), 
  in 
  which 
  a 
  large 
  transverse 
  groove 
  is 
  pi'esent 
  

   on 
  the 
  antciior 
  margin 
  of 
  the 
  foot, 
  which 
  leads 
  into 
  a 
  longi- 
  

   tudinal 
  ciliated 
  canal 
  surrounded 
  by 
  cells 
  of 
  the 
  pedal 
  gland. 
  

   In 
  cross-section 
  the 
  pedal 
  gland 
  presents 
  a 
  similar 
  appearance 
  

   to 
  that 
  of 
  Chenopus 
  as 
  figured 
  by 
  Houssay 
  (23, 
  pi. 
  xiii, 
  

   fig. 
  4, 
  pp. 
  278— 
  281). 
  

  

  Though 
  theie 
  is 
  no 
  definite 
  pedal 
  gland 
  in 
  any 
  of 
  the 
  

   species 
  of 
  the 
  sub-genus 
  Gibbula, 
  such 
  a 
  structure 
  is 
  not 
  

  

  