﻿ANATOMY 
  AND 
  AFFINITIES 
  OF 
  THE 
  TKOCHID^. 
  38 
  

  

  Some 
  Observations 
  on 
  the 
  Anatomy 
  and 
  

   Aflanities 
  of 
  the 
  Trochidse. 
  

  

  By 
  

  

  \¥. 
  B. 
  Raiidlofii, 
  B.Sc.(Loiid. 
  

  

  (From 
  tlic 
  Zoological 
  Lahoraioiy, 
  Royal 
  College 
  of 
  Scienre, 
  London.) 
  

  

  Willi 
  Plates 
  4., 
  5, 
  and 
  6. 
  

  

  The 
  results 
  embodied 
  in 
  this 
  paper 
  are 
  the 
  outcome 
  of 
  a 
  

   series 
  of 
  observations 
  on 
  the 
  anatomy 
  of 
  various 
  species 
  of 
  

   Trochus. 
  It 
  was 
  my 
  original 
  intention^ 
  acting 
  on 
  the 
  sug- 
  

   gestion 
  of 
  the 
  late 
  Martin 
  F. 
  Woodward^ 
  to 
  confine 
  my 
  atten- 
  

   tion 
  mainly 
  to 
  one 
  species, 
  viz. 
  Trochus 
  magus, 
  and 
  

   study 
  that 
  as 
  a 
  type 
  form. 
  I 
  was 
  unaware 
  at 
  that 
  time 
  of 
  the 
  

   existence 
  of 
  a 
  memoir 
  on 
  Trochus, 
  published 
  in 
  the 
  ^Zoologie 
  

   Descriptive' 
  (38), 
  in 
  which 
  a 
  very 
  adequate 
  account 
  of 
  the 
  

   anatomy 
  of 
  T^rochus 
  turbinatus 
  (Born) 
  is 
  given 
  by 
  

   A. 
  Robert. 
  As 
  this 
  article 
  gives 
  a 
  sufficiently 
  detailed 
  account 
  

   of 
  the 
  anatomy 
  of 
  a 
  fairly 
  typical 
  form, 
  it 
  will 
  be 
  unnecessary 
  

   for 
  me 
  to 
  give 
  more 
  than 
  a 
  general 
  resume 
  of 
  the 
  main 
  

   points 
  of 
  the 
  anatomy, 
  but 
  rather 
  to 
  amplify 
  any 
  features 
  that 
  

   have 
  not 
  been 
  fully 
  described, 
  and 
  to 
  point 
  out 
  any 
  differences 
  

   that 
  may 
  exist 
  in 
  the 
  organisation 
  of 
  the 
  various 
  species 
  

   which 
  I 
  have 
  been 
  able 
  to 
  examine, 
  noting 
  whether 
  these 
  

   differences 
  are 
  sufficient 
  to 
  justify 
  the 
  existence 
  of 
  the 
  

   numerous 
  sub-genera 
  into 
  which 
  the 
  genus 
  Trochus 
  has 
  been 
  

   divided 
  upon 
  conchological 
  grounds. 
  

  

  All 
  the 
  species 
  which 
  I 
  have 
  so 
  far 
  examined 
  are 
  British, 
  

  

  