﻿121 
  

  

  NOTE 
  ON 
  HELIX 
  SCYTODES, 
  PFE. 
  

  

  By 
  a. 
  K. 
  Gui)K, 
  F.Z.S., 
  etc. 
  

  

  Read 
  9th 
  June, 
  1916. 
  

  

  Recently, 
  while 
  working; 
  at 
  some 
  of 
  the 
  hind 
  shells 
  in 
  the 
  collection 
  

   of 
  the 
  Biitish 
  Museum, 
  I 
  noticed 
  two 
  specimens 
  of 
  a 
  helicoid 
  which 
  

   I 
  had 
  not 
  seen 
  before, 
  viz. 
  Helix 
  scytodes, 
  Pt'r.,^ 
  from 
  the 
  Solomon 
  

   Islands. 
  These 
  were 
  the 
  type-specimens 
  in 
  the 
  Cuming 
  Collection'. 
  

   I 
  was 
  immediately 
  struck 
  with 
  their 
  resemblance 
  to 
  two 
  unnamed 
  

   shells 
  which 
  were 
  accjuired 
  by 
  me 
  some 
  years 
  ago 
  with 
  various 
  other 
  

   shells 
  at 
  an 
  auction 
  sale, 
  and 
  actual 
  comparison 
  of 
  the 
  specimens 
  

   confirmed 
  their 
  identity. 
  

  

  The 
  species 
  was 
  referred 
  to 
  Trochomorpha 
  by 
  Pfeiffer^ 
  and 
  by 
  

   Pilsbry,^ 
  but 
  a 
  careful 
  examination 
  of 
  the 
  shell 
  convinced 
  me 
  tliat 
  it 
  

   would 
  more 
  correctly 
  be 
  assigned 
  to 
  the 
  genus 
  Plectotropu, 
  the 
  

   reflected 
  outer 
  and 
  basal 
  margins 
  of 
  the 
  peristome, 
  especially, 
  being 
  a 
  

   feature 
  which 
  would 
  at 
  once 
  remove 
  it 
  from 
  Trochomorpha. 
  Both 
  the 
  

   type 
  shells 
  in 
  the 
  Cuming 
  Collection, 
  and 
  those 
  in 
  my 
  own, 
  are 
  devoid 
  

   of 
  the 
  periostracum 
  and 
  do 
  not, 
  consequently, 
  show 
  the 
  scales 
  which 
  

   are 
  so 
  characteristic 
  of 
  the 
  genus 
  Plectotropis, 
  but 
  traces 
  of 
  them 
  cau 
  

   be 
  seen 
  inside 
  the 
  umbilicus. 
  The 
  shell 
  bears 
  a 
  general 
  resemblance 
  

   to 
  such 
  species 
  as 
  P. 
  winteriana, 
  Pfr., 
  P. 
  tapeina, 
  Bens., 
  and 
  

   P. 
  squarrosa, 
  Gld. 
  

  

  No 
  species 
  of 
  the 
  genus 
  Plectotropis, 
  it 
  is 
  true, 
  has 
  been 
  recorded 
  

   from 
  the 
  Solomon 
  Islands, 
  but 
  Cuming 
  is 
  well 
  known 
  to 
  have 
  been 
  

   unreliable 
  with 
  his 
  localities, 
  and 
  this 
  may 
  well 
  be 
  another 
  instance 
  

   of 
  a 
  wrong 
  habitat. 
  

  

  The 
  species 
  has 
  been 
  well 
  figured 
  by 
  Reeve,* 
  whose 
  figure 
  has 
  been 
  

   copied 
  by 
  Tryon.® 
  

  

  1 
  Proc. 
  Zool. 
  Soc, 
  1854, 
  p. 
  56. 
  

   - 
  Malak. 
  Blatt., 
  ii, 
  1855, 
  p. 
  133. 
  

  

  * 
  Man. 
  Coneh., 
  ser. 
  II, 
  ix, 
  1894, 
  p. 
  5. 
  

  

  * 
  Conch. 
  Icon., 
  vol. 
  vii, 
  1854, 
  pi. 
  188, 
  fig. 
  1310. 
  

  

  * 
  Man. 
  Conch., 
  ser. 
  II, 
  vol. 
  iii, 
  1887, 
  p. 
  77, 
  pi. 
  x.iv, 
  fig. 
  20. 
  

  

  