﻿134 
  

  

  PROCEEDINGS 
  OF 
  THE 
  MALACOLOGICAL 
  SOCIETY. 
  

  

  acicular 
  type. 
  The 
  second 
  sac 
  has 
  slighter 
  walls, 
  and 
  recalls 
  the 
  

   accessory 
  dartless 
  sacs 
  of 
  ITygromia 
  rufe&cens^ 
  ftisca, 
  and 
  (from 
  

   Moquin-Tandon's 
  account) 
  Jlelicella 
  carascalenais. 
  

  

  Helicella 
  neglecta 
  (Drap.)- 
  — 
  FiG- 
  1. 
  Genitalia 
  of 
  specimen 
  whose 
  shell 
  measured 
  

   lO'Smm. 
  in 
  diameter: 
  a.d. 
  accessory 
  dart-sac 
  ; 
  d. 
  dart-sac 
  ; 
  g.o. 
  genital 
  

   orifice 
  ; 
  vi.g. 
  mucous 
  glands 
  ; 
  p. 
  penis 
  ; 
  r. 
  retractor 
  muscles 
  ; 
  s. 
  sperma- 
  

   theca 
  ; 
  v.d. 
  vas 
  deferens. 
  FiG. 
  2. 
  Unci 
  of 
  Eadula. 
  Fig. 
  3. 
  Maxilla. 
  

  

  ItADDLA 
  AND 
  JFaXILLA. 
  

  

  The 
  radula 
  is 
  2'47 
  mm. 
  long 
  and 
  0-96 
  mm. 
  wide. 
  There 
  are 
  

   ninety-four 
  rows 
  of 
  unci. 
  The 
  admedians 
  merge 
  gradually 
  into 
  the 
  

   externals. 
  Ten 
  typical 
  admedians 
  may 
  be 
  recognized, 
  leaving 
  twenty 
  

   externals; 
  of 
  the 
  latter, 
  the 
  lateral 
  ten 
  or 
  twelve 
  have 
  a 
  well-marked 
  

   median 
  cone. 
  This 
  is 
  the 
  condition 
  which 
  I 
  have 
  elsewhere 
  described 
  

   as 
  "bifid 
  mesocone", 
  but 
  in 
  this 
  case 
  the 
  accessory 
  cone 
  has 
  more 
  

   the 
  appearance 
  of 
  an 
  appendage 
  median 
  to 
  the 
  mesocone. 
  In 
  my 
  

   figure 
  of 
  H. 
  caperata 
  (Proc. 
  Malac. 
  Soc, 
  viii, 
  p. 
  384) 
  this 
  feature 
  is 
  

   more 
  regularly 
  represented 
  than 
  I 
  have 
  since 
  found 
  to 
  be 
  usual 
  ; 
  it 
  

   is 
  quite 
  common 
  to 
  find 
  an 
  irregularly 
  scolloped 
  median 
  margin 
  to 
  

   the 
  mesocone 
  in 
  that 
  species. 
  The 
  general 
  ajjpearance 
  of 
  the 
  unci 
  

   is 
  shown 
  in 
  Fig. 
  2. 
  

  

  The 
  maxilla 
  is 
  narrow, 
  presenting 
  no 
  central 
  increase 
  of 
  length. 
  

   It 
  is 
  provided 
  with 
  eight 
  or 
  nine 
  ribs. 
  Its 
  width 
  is 
  about 
  1 
  mm. 
  

   (Fig. 
  3.) 
  

  

  