﻿REMARKABLE 
  MARINE 
  LNVERTEBRATA 
  NEW 
  TO 
  THE 
  BRITISH 
  SEAS. 
  311 
  

  

  simple 
  ; 
  no 
  conspicuous 
  genital 
  glands 
  ; 
  two 
  long 
  marginal 
  tentacles, 
  and 
  

   numerous 
  intermediate 
  rudimentary 
  tubercles, 
  all 
  with 
  ocelli 
  at 
  their 
  bases 
  ; 
  

   stomach 
  at 
  the 
  end 
  of 
  a 
  very 
  long, 
  extensile, 
  cylindrical 
  tubular 
  proboscidiform 
  

   peduncle, 
  with 
  a 
  simple 
  or 
  obscurely 
  lobed 
  orifice. 
  

  

  We 
  have 
  deemed 
  it 
  necessary 
  to 
  constitute 
  this 
  genus 
  for 
  a 
  very 
  curious 
  little 
  

   naked-eyed 
  medusa 
  of 
  the 
  family 
  Sai'siadw, 
  so 
  distinct 
  in 
  its 
  characters, 
  as 
  not 
  

   to 
  be 
  referable 
  to 
  any 
  of 
  the 
  defined 
  groups. 
  We 
  have 
  dedicated 
  it 
  to 
  Janus 
  

   Plancus, 
  who, 
  in 
  his 
  tract 
  " 
  De 
  Conchis 
  Minus 
  Notis," 
  published 
  in 
  1739, 
  was 
  

   the 
  first 
  naturalist 
  who 
  figured 
  a 
  naked-eyed 
  medusa. 
  

  

  Plancia 
  gracilis. 
  Sp. 
  Nov. 
  — 
  Disk 
  hemispherical, 
  depressed, 
  colourless, 
  

   smooth, 
  its 
  margin 
  furnished 
  with 
  two 
  long 
  tubular 
  tentacula, 
  one 
  on 
  each 
  side 
  

   opposite 
  the 
  terminations 
  of 
  gastrovascular 
  canals 
  ; 
  at 
  the 
  origin 
  of 
  each 
  of 
  these 
  

   is 
  a 
  small 
  fixed 
  tentacular 
  process, 
  connecting 
  the 
  umbrella 
  with 
  the 
  subumbrella, 
  

   as 
  in 
  the 
  genus 
  Steenstrupia. 
  The 
  remainder 
  of 
  the 
  margin 
  is 
  occupied 
  by 
  about 
  

   sixty 
  minute 
  tubercles 
  or 
  rudimentary 
  tentacula, 
  beside 
  each 
  of 
  which 
  on 
  an 
  

   oblong 
  process 
  is 
  a 
  minute 
  black 
  ocellus. 
  Four 
  simple 
  gastrovascular 
  canals, 
  

   connected 
  with 
  a 
  marginal 
  canal, 
  divide 
  the 
  disk 
  into 
  as 
  many 
  equal 
  segments. 
  

   The 
  entrance 
  of 
  the 
  cavity 
  is 
  protected 
  by 
  a 
  broad 
  veil. 
  The 
  peduncle 
  is 
  very 
  

   long 
  and 
  extensile, 
  resembling 
  in 
  shape 
  that 
  of 
  Sarsia 
  ; 
  it 
  is 
  very 
  acute 
  at 
  its 
  

   base, 
  and 
  is 
  of 
  a 
  general 
  pink 
  hue, 
  with 
  darker 
  lines, 
  as 
  if 
  of 
  genital 
  glands 
  lining 
  

   its 
  tube. 
  It 
  is 
  terminated 
  by 
  a 
  short 
  orange-coloured 
  campanulate 
  stomach, 
  

   opening 
  by 
  an 
  irregularly 
  four-lobed 
  orifice. 
  

  

  This 
  is 
  an 
  active 
  and 
  elegant 
  little 
  creature. 
  Its 
  disk 
  measures 
  rather 
  less 
  

   than 
  a 
  quarter 
  of 
  an 
  inch 
  across. 
  When 
  swimming, 
  it 
  carries 
  its 
  two 
  tentacula 
  

   streaming 
  behind 
  it 
  for 
  a 
  great 
  length. 
  We 
  procured 
  several 
  examples 
  in 
  the 
  

   Sound 
  of 
  Mull 
  and 
  off 
  Staffa. 
  

  

  Oceania 
  ducalis. 
  Sp. 
  Nov. 
  — 
  Umbrella 
  campanulate, 
  subglobose, 
  round 
  above, 
  

   smooth, 
  colourless, 
  transparent. 
  Subumbrella 
  rather 
  small 
  in 
  proportion, 
  its 
  

   orifice 
  protected 
  by 
  a 
  conspicuous 
  veil 
  ; 
  its 
  margin 
  edged 
  with 
  rose-colour, 
  and 
  

   bearing 
  16 
  (3 
  x 
  4 
  + 
  4) 
  pinkish 
  tentacula, 
  springing 
  from 
  bulbous 
  bases, 
  each 
  of 
  

   which 
  is 
  marked 
  by 
  a 
  conspicuous 
  crimson 
  or 
  purple 
  crescentic 
  ocellus 
  : 
  between 
  

   each 
  pair 
  of 
  tentacles 
  is 
  a 
  minute 
  tubercular 
  process. 
  Down 
  the 
  sides 
  of 
  the 
  

   subumbrella 
  run 
  the 
  four 
  simple 
  gastrovascular 
  canals, 
  tinged 
  with 
  red. 
  From 
  

   its 
  centre 
  depends 
  the 
  oblong, 
  massive, 
  reddish-tawny 
  peduncle, 
  in 
  the 
  upper 
  part 
  

   of 
  which 
  are 
  obscurely 
  seen 
  the 
  convoluted 
  reproductive 
  glands. 
  The 
  orifice 
  of 
  

   the 
  peduncle 
  is 
  campanulate, 
  and 
  bordered 
  by 
  four 
  slightly-fimbriated 
  lips. 
  The 
  

   height 
  of 
  the 
  body 
  is 
  less 
  than 
  a 
  quarter 
  of 
  an 
  inch. 
  

  

  It 
  was 
  taken 
  at 
  Tobermory. 
  We 
  had 
  previously 
  met 
  with 
  the 
  same 
  species 
  

   on 
  the 
  coast 
  of 
  Dorsetshire. 
  

  

  Slabberia 
  catenata. 
  — 
  Hitherto 
  only 
  a 
  single 
  species 
  of 
  the 
  genus 
  Slabberia, 
  one 
  

   of 
  the 
  most 
  curious 
  types 
  of 
  the 
  Medusa 
  Gymnopthalmata, 
  has 
  been 
  met 
  with, 
  

  

  VOL. 
  XX. 
  PART 
  II. 
  4 
  P 
  

  

  