﻿236 
  PKOCEEDINGS 
  OF 
  THE 
  MALACOLOGICAL 
  SOCIEIT. 
  

  

  innervates 
  tlie 
  anterior 
  adductor 
  muscle 
  and 
  the 
  fore-part 
  of 
  the 
  

   mantle 
  - 
  lobe, 
  and 
  continues 
  as 
  the 
  circumpallial 
  nerve, 
  which 
  

   apparently 
  joins 
  the 
  posterior 
  pallial 
  nerve. 
  The 
  viscero-pai'ietal 
  

   ganglia 
  (Fig. 
  2, 
  V.C.P.) 
  are 
  situated 
  near 
  the 
  an 
  tero- 
  ventral 
  edge 
  

   of 
  the 
  posterior 
  adductor 
  muscle. 
  Each 
  cerebro-visceral 
  connective 
  

   (Fig. 
  2, 
  C.V.C.) 
  passes 
  outside 
  the 
  pedis 
  retractor 
  anterior 
  muscle 
  

   alongside 
  the 
  viscera, 
  and 
  between 
  the 
  transverse 
  pedal 
  muscle 
  until 
  

   near 
  the 
  retractor 
  posterior 
  muscle, 
  when 
  it 
  pierces 
  the 
  pedal 
  

   integument 
  and 
  then 
  proceeds 
  outside 
  the 
  retractor 
  muscle 
  to 
  the 
  

   viscero-parietal 
  ganglion. 
  Ventrally 
  from 
  each 
  cerebro-pleural 
  ganglion 
  

   passes 
  the 
  pedal 
  connective 
  (Fig. 
  2, 
  C.P.C.), 
  which 
  goes 
  along 
  the 
  

   longitudinal 
  and 
  between 
  the 
  transverse 
  muscles 
  of 
  the 
  foot 
  until 
  it 
  

   reaches 
  the 
  pedal 
  ganglion 
  (Fig. 
  2, 
  P.G.) 
  situated 
  just 
  in 
  front 
  of 
  

   the 
  digestive 
  gland, 
  but 
  nearly 
  buried 
  in 
  a 
  transverse 
  muscle-bundle. 
  

   The 
  branchial 
  nerves 
  leave 
  the 
  viscero-parietal 
  ganglia 
  on 
  the 
  posterior 
  

   side, 
  and, 
  curving, 
  run 
  along 
  the 
  base 
  of 
  the 
  gills. 
  Posteriorly 
  from 
  

   the 
  viscero-parietal 
  ganglia 
  run 
  the 
  posterior 
  pallial 
  nerves, 
  whicli 
  

   innervate 
  the 
  posterior 
  adductor 
  muscle, 
  the 
  siphon, 
  and 
  the 
  posterior 
  

   portion 
  of 
  the 
  mantle-lobes. 
  The 
  nerve 
  which 
  innervates 
  each 
  

   siphonal 
  tube 
  is 
  divided 
  into 
  six 
  branches, 
  each 
  branch 
  running 
  along 
  

   it 
  to 
  the 
  distal 
  end. 
  

  

  The 
  sense 
  organs, 
  as 
  well 
  as 
  the 
  distribution 
  of 
  the 
  finer 
  nerve 
  

   bi'anches 
  in 
  the 
  siphon 
  and 
  the 
  mantle-lobes, 
  are 
  fully 
  described 
  by 
  

   llawitz 
  in 
  his 
  work 
  Ber 
  Mantelrand 
  der 
  Acephalen. 
  

  

  PsAMMOBiA 
  Fereoensis 
  (Cliemnitz). 
  

  

  External 
  Characters. 
  — 
  The 
  one 
  animal 
  examined 
  measures 
  21 
  by 
  

   10 
  mm. 
  The 
  dorsal 
  surface 
  is 
  somewhat 
  triangular, 
  with 
  a 
  depression 
  

   on 
  the 
  posterior 
  side. 
  The 
  anterior 
  part 
  is 
  curved, 
  whilst 
  the 
  posterior 
  

   is 
  quite 
  angular. 
  As 
  in 
  P. 
  vespertina 
  the 
  ventral 
  portion 
  of 
  the 
  latter 
  

   projects 
  backwards. 
  The 
  ventral 
  side 
  is 
  only 
  very 
  slightly 
  curved. 
  

   Further, 
  the 
  animal 
  is 
  not 
  so 
  deep 
  as 
  P. 
  vespertina. 
  

  

  The 
  concrescence 
  of 
  the 
  mantle-lobes 
  appears 
  to 
  be 
  the 
  same 
  as 
  in 
  

   P. 
  vespertina., 
  but 
  the 
  proximal 
  portion 
  of 
  the 
  siphon 
  extends 
  a 
  little 
  

   more 
  anteriorly. 
  The 
  siphonal 
  tubes 
  are 
  long, 
  and 
  in 
  Fig. 
  8 
  it 
  will 
  

   be 
  observed 
  how 
  the 
  central 
  part 
  widens 
  when 
  wholly 
  or 
  partly 
  

   withdrawn 
  {Ex.8.'). 
  The 
  anterior 
  adductor 
  muscle 
  (Fig. 
  8, 
  A. 
  A.) 
  is 
  

   wider 
  than 
  it 
  is 
  deep, 
  and 
  shows 
  a 
  constriction 
  at 
  the 
  centre 
  of 
  the 
  

   under-surtace. 
  Compared 
  with 
  P. 
  vespertina 
  it 
  is 
  comparative!}' 
  a 
  

   smaller 
  muscle, 
  being 
  shorter 
  and 
  shallower, 
  and 
  at 
  the 
  same 
  time 
  

   situated 
  in 
  a 
  more 
  oblique 
  position. 
  The 
  posterior 
  adductor 
  muscle 
  

   (Fig. 
  8, 
  P. 
  A.) 
  is 
  slightly 
  angular 
  at 
  tlie 
  dorso-anteiior 
  edge, 
  and 
  

   differs 
  from 
  that 
  of 
  P. 
  vespertina 
  in 
  being 
  relatively 
  not 
  so 
  deep, 
  but 
  

   shorter 
  and 
  wider. 
  

  

  Alimentary 
  Canal. 
  — 
  The 
  oesophagus 
  (Figs. 
  8, 
  9, 
  and 
  10, 
  Oe.) 
  is 
  

   moderately 
  long, 
  narrow, 
  and 
  curved. 
  The 
  stomach 
  is 
  divided 
  into 
  

   several 
  lobes, 
  as 
  in 
  P. 
  vespertina, 
  but 
  the 
  oesophageal 
  division 
  (Figs. 
  9 
  

   and 
  10, 
  Oe.St.) 
  is 
  small 
  and 
  triangular 
  in 
  shape. 
  The 
  demarcation 
  

   of 
  the 
  cardiac 
  division 
  (Fig. 
  10, 
  C.St.) 
  is 
  well 
  defined 
  on 
  the 
  right 
  

   side, 
  but 
  not 
  on 
  the 
  left. 
  The 
  pyloric 
  division 
  (Figs. 
  9 
  and 
  10, 
  P.St.) 
  

  

  