﻿MOLLUSC 
  A. 
  43 
  

  

  are 
  not 
  nodulous. 
  The 
  whorls 
  in 
  the 
  latter 
  are 
  not 
  so 
  rounded, 
  

   decidedly 
  more 
  angular 
  above, 
  much 
  more 
  finelj^ 
  spirally 
  ridged, 
  

   and 
  bear 
  upon 
  the 
  varices 
  shorter, 
  thicker, 
  and 
  more 
  curved 
  

   spines, 
  which 
  are 
  not 
  purple-black 
  tipped, 
  but 
  white, 
  except 
  

   along 
  the 
  back, 
  where 
  there 
  is 
  a 
  slight 
  ridge 
  of 
  pale 
  brown. 
  

   M. 
  trihidus 
  has 
  a 
  different 
  apex, 
  more 
  convex 
  whorls, 
  different 
  

   coloration, 
  and 
  much 
  coarser 
  and 
  nodose 
  spiral 
  ridging. 
  The 
  

   number 
  and 
  position 
  of 
  the 
  spines 
  is 
  seen 
  to 
  be 
  very 
  similar 
  in 
  

   all 
  three 
  species 
  when 
  closely 
  and 
  carefully 
  compared. 
  

  

  13. 
  Murex 
  acanthostephes. 
  (Plate 
  V. 
  fig. 
  B.) 
  

  

  Murex 
  (Tribuliis) 
  acanthostephes, 
  Watson, 
  Jqurn. 
  Linn. 
  Soc, 
  Zool. 
  

   vol. 
  xvi. 
  p. 
  596. 
  

  

  Hah. 
  Arafura 
  Sea, 
  N.W. 
  Australia, 
  in 
  32-36 
  fms. 
  ; 
  bottom 
  — 
  mud, 
  

   sand, 
  and 
  shells. 
  

  

  The 
  ' 
  Challenger 
  ' 
  specimen 
  was 
  dredged 
  very 
  near 
  the 
  same 
  spot, 
  

   in 
  28 
  fms. 
  

  

  Shell 
  in 
  form 
  and 
  general 
  aspect 
  rather 
  like 
  M. 
  tenuispinn, 
  

   Lamarck, 
  but 
  with 
  a 
  shorter 
  spire, 
  fewer 
  spines, 
  and 
  a 
  non-canali- 
  

   culate 
  suture 
  ; 
  whitish, 
  stained 
  irregularly 
  with 
  light 
  olive-brown. 
  

   Whorls 
  convex, 
  subangular 
  and 
  carinated 
  above 
  the 
  middle, 
  with 
  

   two 
  or 
  three 
  fine 
  spiral 
  raised 
  lines 
  above 
  the 
  angle 
  upon 
  the 
  

   sloping 
  and 
  somewhat 
  flattened 
  upper 
  portion, 
  and 
  two 
  or 
  three 
  

   similar 
  lines 
  below 
  the 
  angle. 
  Varices 
  three 
  on 
  a 
  whorl, 
  bearing 
  

   five 
  spines 
  upon 
  the 
  convex 
  part 
  and 
  six 
  on 
  the 
  verj- 
  straight 
  beak, 
  

   with 
  three 
  or 
  four 
  minute 
  secondary 
  ones 
  reflesed 
  and 
  appressed 
  to 
  

   the 
  surface. 
  The 
  uppermost 
  of 
  all, 
  arising 
  from 
  the 
  carina 
  at 
  the 
  

   upper 
  part 
  of 
  the 
  whorls, 
  is 
  the 
  longest, 
  slightly 
  curved, 
  very 
  erect, 
  

   and 
  almost 
  parallel 
  with 
  the 
  axis 
  of 
  the 
  shell. 
  The 
  next, 
  No. 
  2, 
  is 
  

   minute, 
  jN^o. 
  3 
  a 
  little 
  shorter 
  than 
  No. 
  1 
  and 
  arcuate, 
  No. 
  4 
  much 
  

   smaller, 
  and 
  No. 
  5 
  a 
  little 
  smaller 
  than 
  No. 
  3. 
  

  

  The 
  spines 
  on 
  the 
  cauda 
  are 
  straighter 
  than 
  those 
  above, 
  hori- 
  

   zontal, 
  or 
  at 
  right 
  angles 
  to 
  the 
  axis, 
  the 
  third, 
  counting 
  from 
  

   above, 
  being 
  a 
  trifle 
  the 
  longest, 
  the 
  rest 
  on 
  each 
  side 
  becoming 
  

   successively 
  shorter. 
  The 
  body-whorl 
  is 
  transversely 
  lirate 
  through- 
  

   out, 
  the 
  lira; 
  varying 
  in 
  coarseness, 
  the 
  strongest 
  corresponding 
  to 
  

   the 
  longest 
  spines, 
  and 
  being 
  only 
  slightly 
  wavy, 
  whilst 
  some 
  of 
  the 
  

   intermediary 
  ones 
  are 
  almost 
  subnodular. 
  The 
  three 
  nuclear 
  whorls 
  

   arc 
  light 
  brown, 
  glossy, 
  and 
  larger 
  than 
  those 
  of 
  M. 
  tenidspina. 
  

   The 
  fourth 
  whorl 
  has 
  about 
  eleven 
  short, 
  open, 
  and 
  a 
  little 
  upturned 
  

   spines, 
  forming 
  a 
  very 
  pretty 
  coronation 
  at 
  a 
  subcentral 
  angle, 
  and 
  

   has 
  no 
  spiral 
  lines 
  above 
  or 
  below 
  it, 
  but 
  a 
  second 
  series 
  of 
  hollow 
  

   spines 
  below 
  at 
  the 
  suture, 
  smaller 
  than 
  those 
  above. 
  Length 
  

   37millim. 
  ; 
  diameter 
  12, 
  exclusive 
  of 
  spines. 
  

  

  M. 
  tenuisjjina, 
  a 
  near 
  ally, 
  has 
  longer 
  and 
  more 
  numerous 
  spines, 
  

   a 
  longer 
  and 
  more 
  pointed 
  spire 
  terminating 
  in 
  a 
  smaller 
  apex, 
  a 
  

   conspicuously 
  channelled 
  suture, 
  and 
  its 
  sculpture 
  is 
  more 
  pro- 
  

   nounced, 
  the 
  spiral 
  ridges 
  being 
  more 
  granular 
  and 
  the 
  lines 
  of 
  

  

  