﻿Cheeseman. 
  — 
  On 
  new 
  Opistliobrancluate 
  Mollusca. 
  879 
  

  

  microscopic 
  wliite 
  dots. 
  Mantle 
  smooth, 
  not 
  nearly 
  so 
  long 
  as 
  the 
  foot, 
  and 
  

   not 
  concealing 
  the 
  branchios, 
  rather 
  broader 
  on 
  the 
  right 
  side 
  ; 
  oral 
  veil 
  

   broad, 
  extending 
  over 
  and 
  concealing 
  the 
  mouth, 
  in 
  front 
  semicircular, 
  and 
  

   with 
  a 
  delicate 
  fringed 
  margin, 
  but 
  at 
  each 
  side 
  produced 
  into 
  a 
  short 
  

   tentacle-like 
  lobe 
  ; 
  mouth 
  large, 
  round, 
  in 
  a 
  state 
  of 
  rest 
  concealed 
  in 
  the 
  

   sulcus 
  between 
  the 
  oral 
  veil 
  and 
  the 
  foot, 
  but 
  capable 
  of 
  being 
  greatly 
  pro- 
  

   truded 
  in 
  a 
  proboscidiform 
  manner 
  ; 
  buccal 
  plates 
  two, 
  large, 
  finely 
  and 
  

   regularly 
  reticulated 
  or 
  faceted 
  ; 
  odontophore 
  broad, 
  with 
  numerous 
  rows 
  of 
  

   similar 
  unciform 
  teeth 
  ; 
  tentacles 
  dorsal, 
  wide 
  apart, 
  short 
  and 
  stout, 
  project- 
  

   ing 
  outwards, 
  folded 
  down 
  the 
  outer 
  side, 
  tips 
  obliquely 
  truncate 
  ; 
  eyes 
  

   minute, 
  black, 
  placed 
  Avithin 
  the 
  integument 
  at 
  the 
  inner 
  bases 
  of 
  the 
  

   tentacles, 
  quite 
  internal, 
  and 
  not 
  to 
  be 
  seen 
  without 
  dissection; 
  foot 
  long, 
  

   extremely 
  flexible, 
  sole 
  pale 
  ashy 
  grey 
  ; 
  branchial 
  plume 
  often 
  over 
  an 
  inch 
  

   in 
  length, 
  and 
  free 
  for 
  half 
  that 
  distance 
  ; 
  pectinations 
  about 
  17, 
  finely 
  

   ciliated 
  ; 
  shell 
  none 
  ; 
  length 
  2*5 
  to 
  3'25 
  inches. 
  

  

  This 
  species 
  is 
  very 
  abundant 
  in 
  Auckland 
  Harbour, 
  usually 
  affecting 
  

   sandy 
  or 
  muddy 
  localities. 
  In 
  the 
  winter 
  and 
  spring 
  months 
  large 
  numbers 
  

   are 
  often 
  exposed 
  at 
  neap 
  tides, 
  having 
  probably 
  come 
  into 
  shallow 
  water 
  to 
  

   deposit 
  their 
  ova. 
  Captain 
  Hutton, 
  of 
  the 
  Otago 
  Museum, 
  informs 
  me 
  that 
  

   he 
  has 
  collected 
  the 
  same 
  species 
  at 
  Port 
  Nicholson. 
  It 
  is 
  hardy 
  and 
  not 
  

   easily 
  killed, 
  and 
  may 
  be 
  kept 
  in 
  confinement 
  for 
  a 
  long 
  time. 
  When 
  in 
  a 
  

   healthy 
  state 
  it 
  is 
  by 
  no 
  means 
  inactive, 
  crawling 
  along 
  by 
  means 
  of 
  its 
  

   muscular 
  foot 
  much 
  more 
  quickly 
  than 
  might 
  be 
  expected. 
  It 
  has 
  a 
  curious 
  

   habit 
  of 
  floating 
  in 
  a 
  reversed 
  position, 
  just 
  under 
  the 
  surface 
  of 
  the 
  water; 
  

   and 
  I 
  have 
  also 
  observed 
  it 
  swimming 
  by 
  means 
  of 
  rather 
  violent 
  vertical 
  

   undulations 
  of 
  its 
  body. 
  

  

  3. 
  AcLESiA 
  GLAucA, 
  u. 
  sp. 
  (Plate 
  XVI., 
  fig. 
  4.) 
  

  

  Body 
  from 
  3 
  to 
  5 
  inches 
  long, 
  about 
  ovate 
  when 
  at 
  rest, 
  but 
  capable 
  of 
  

   considerable 
  extension, 
  a 
  little 
  contracted 
  behind 
  the 
  head, 
  then 
  elevated, 
  

   and 
  suddenly 
  sloping 
  to 
  a 
  point 
  posteriorly 
  ; 
  entirely 
  covered 
  with 
  numerous 
  

   simple 
  and 
  branched 
  tentacle-like 
  processes, 
  the 
  largest 
  of 
  which 
  are 
  some- 
  

   times 
  eight 
  lines 
  long. 
  Colour 
  on 
  the 
  sides 
  pale 
  greyish-brown, 
  passing 
  on 
  

   the 
  back 
  into 
  a 
  dull 
  sea-green 
  ; 
  the 
  whole 
  surface 
  with 
  numerous 
  irregularly 
  

   shaped 
  black 
  blotches 
  that 
  are 
  largest 
  on 
  the 
  back. 
  Along 
  the 
  back 
  there 
  

   is 
  also 
  a 
  double 
  row 
  of 
  from 
  8 
  to 
  12 
  emerald-green 
  specks, 
  each 
  surrounded 
  

   with 
  a 
  zone 
  of 
  umber. 
  Dorsal 
  tentacles 
  f 
  inch 
  long, 
  folded 
  down 
  the 
  outer 
  

   side 
  so 
  as 
  to 
  appear 
  tubular, 
  beset 
  with 
  filiform 
  appendages. 
  Labial 
  ten- 
  

   tacles 
  similar 
  in 
  shape, 
  but 
  rather 
  larger. 
  Branchial 
  cavity 
  large, 
  protected 
  

   by 
  the 
  folded-in 
  edges 
  of 
  the 
  mantle, 
  brancluEe 
  quite 
  internal; 
  foot 
  long 
  and 
  

   narrow, 
  pointed 
  behind, 
  without 
  side-lobes 
  as 
  in 
  Ajdysia, 
  sole 
  pale 
  sea- 
  

   green; 
  mouth 
  roundish, 
  lolaced 
  under 
  the 
  head; 
  odontophore 
  with 
  very 
  

  

  