﻿68 
  W. 
  B. 
  HANDLES. 
  

  

  has 
  pi'eviouslybeeu 
  placed 
  by 
  concliologistS; 
  cannot 
  be 
  retained, 
  

   as 
  the 
  interual 
  organisation 
  of 
  this 
  species, 
  and 
  also 
  that 
  o£ 
  

   T. 
  turbinatns 
  (Born), 
  as 
  described 
  by 
  Eobert 
  (38), 
  another 
  

   species 
  previously 
  included 
  in 
  the 
  sub-section 
  Trochoco- 
  

   chlea, 
  is 
  almost 
  identical 
  with 
  the 
  anatomical 
  structure 
  of 
  

   T. 
  magus 
  or 
  other 
  species 
  of 
  Gibbula. 
  

  

  As 
  I 
  was 
  unable 
  to 
  obtain 
  any 
  specimens 
  of 
  species 
  belong- 
  

   ing 
  to 
  the 
  so-called 
  sub-genus 
  Margarita 
  (Leach), 
  I 
  cannot 
  

   say 
  whether 
  sufficient 
  anatomical 
  differences 
  occur 
  to 
  warrant 
  

   the 
  existence 
  of 
  this 
  separate 
  sub-genus. 
  

  

  So 
  far, 
  then, 
  anatomical 
  investigations 
  have 
  revealed 
  such 
  

   striking 
  similarity 
  of 
  structure 
  as 
  to 
  necessitate 
  the 
  reduction 
  

   of 
  sub-genera 
  amongst 
  British 
  Trochidfe, 
  and 
  it 
  is 
  highly 
  pro- 
  

   bable 
  that 
  an 
  anatomical 
  examination 
  of 
  exotic 
  species 
  will 
  

   still 
  further 
  considerably 
  reduce 
  the 
  very 
  numerous 
  sub- 
  

   genera 
  into 
  which 
  these 
  have 
  been 
  classified. 
  

  

  Although 
  both 
  T. 
  zizyphinus 
  and 
  T. 
  granulatus 
  differ 
  

   in 
  many 
  ways 
  from 
  T. 
  magus 
  and 
  other 
  species 
  of 
  Gibbula, 
  

   yet 
  the 
  smaller 
  species, 
  T. 
  striatus 
  and 
  T. 
  exasperatus, 
  

   though 
  they 
  have 
  been 
  included 
  in 
  the 
  sub-genus 
  C 
  allies 
  - 
  

   to 
  ma, 
  agree 
  in 
  some 
  respects 
  more 
  closely 
  with 
  T. 
  magus 
  and 
  

   its 
  allies 
  than 
  with 
  T. 
  zizyphinus. 
  This 
  is 
  chiefly 
  in 
  respect 
  

   to 
  their 
  external 
  characters; 
  both 
  of 
  these 
  small 
  forms 
  possess 
  

   epipodial 
  papillae 
  and 
  an 
  appendix 
  on 
  the 
  right 
  ocular 
  

   peduncle, 
  while 
  these 
  structures 
  are 
  absent 
  in 
  T. 
  zizyphinus. 
  

   Moreover 
  the 
  glandular 
  structure 
  on 
  the 
  dorsal 
  surface 
  of 
  

   the 
  foot 
  more 
  nearly 
  resembles 
  that 
  seen 
  in 
  T. 
  magus. 
  In 
  

   respect 
  to 
  the 
  structure 
  of 
  the 
  radula 
  of 
  these 
  species, 
  the 
  

   condition 
  is 
  an 
  approximation 
  to 
  the 
  Gibbula 
  rather 
  than 
  the 
  

   Calliostoma 
  type. 
  On 
  the 
  other 
  hand, 
  the 
  presence 
  of 
  a 
  

   transverse 
  notch 
  on 
  the 
  anterior 
  margin 
  of 
  the 
  foot, 
  and 
  also 
  

   the 
  enlargement 
  of 
  the 
  terminal 
  portion 
  of 
  the 
  ureter 
  into 
  an 
  

   ampulla, 
  together 
  with 
  the 
  arrangement 
  of 
  the 
  alimentary 
  

   canal 
  and 
  spiral 
  cascum, 
  tend 
  to 
  show 
  their 
  relationship 
  with 
  

   T. 
  zizyphinus 
  and 
  T. 
  granulatus, 
  and 
  as 
  their 
  shell 
  is 
  

   pyramidal 
  in 
  shape, 
  it 
  seems 
  necessary 
  to 
  include 
  them 
  in 
  

   the 
  sub-o-enus 
  Calliostoma. 
  

  

  