﻿G. 
  M. 
  Thomson. 
  — 
  On 
  the 
  Neiv 
  Zealand 
  Eutomostraca. 
  251 
  

  

  Genits 
  Idotea, 
  Fabi\ 
  

   Idotea, 
  Miers' 
  Cat. 
  N. 
  Z. 
  Crust., 
  p. 
  91. 
  

   Idotea 
  lacusiris, 
  nov. 
  sp. 
  

  

  Body 
  narrow-elliptical, 
  little 
  more 
  than 
  twice 
  as 
  long 
  as 
  broad. 
  Front 
  

   of 
  head 
  excavate, 
  not 
  toothed. 
  First 
  segment 
  of 
  thorax 
  somewhat 
  longer 
  

   than 
  those 
  succeeding, 
  which 
  are 
  subequal 
  ; 
  epimeral 
  pieces 
  nearly 
  square, 
  

   the 
  last 
  three 
  slightly 
  produced 
  posteriorly. 
  

  

  Abdomen 
  3-jointed, 
  terminal 
  joint 
  (formed 
  of 
  three 
  coalescent 
  segments) 
  

   hardly 
  narrowing 
  to 
  the 
  rounded 
  extremity. 
  Inner 
  antennas 
  not 
  half 
  as 
  

   long 
  as 
  base 
  of 
  the 
  outer, 
  4-jointed, 
  joints 
  subequal. 
  Outer 
  antennae 
  

   one 
  thu'd 
  as 
  long 
  as 
  the 
  body, 
  flagellum 
  9-11-jointed, 
  with 
  a 
  dense 
  fringe 
  

   of 
  very 
  short 
  setae 
  on 
  the 
  outer 
  margin. 
  Colour 
  dark 
  gray, 
  mottled 
  with 
  

   brown, 
  with 
  a 
  darker 
  median 
  band 
  extending 
  from 
  the 
  head 
  to 
  near 
  the 
  

   extremity 
  of 
  the 
  abdomen. 
  Length 
  -6 
  inch. 
  

  

  In 
  numerous 
  females, 
  an 
  incubatory 
  pouch 
  extended 
  along 
  the 
  whole 
  

   under 
  surface 
  of 
  the 
  thorax. 
  The 
  young 
  animals, 
  taken 
  out 
  of 
  this 
  sac, 
  

   have 
  their 
  bodies 
  somewhat 
  elongated 
  in 
  shape, 
  with 
  all 
  the 
  segments 
  

   developed, 
  and 
  appendages 
  present, 
  but 
  having 
  the 
  outer 
  antennae 
  furnished 
  

   with 
  a 
  flagellum 
  of 
  only 
  one 
  joint 
  and 
  a 
  few 
  short 
  setaa. 
  

  

  Art. 
  XXI. 
  — 
  On 
  the 
  New 
  Zealand 
  Entomostraca. 
  By 
  George 
  M. 
  Thomson. 
  

   [Read 
  before 
  the 
  Otago 
  Institute, 
  26i/i 
  November, 
  1878.] 
  

   Plate 
  XI. 
  

   The 
  study 
  of 
  the 
  lower 
  orders 
  of 
  Crustaceans 
  is, 
  as 
  a 
  rule, 
  confined 
  to 
  a 
  few 
  

   specialists, 
  hence 
  it 
  is 
  only 
  now 
  and 
  then 
  that 
  they 
  form 
  the 
  subject 
  of 
  

   communications 
  to 
  societies. 
  In 
  regard 
  to 
  this 
  ^colony, 
  the 
  fact 
  is 
  that 
  till 
  

   the 
  publication 
  of 
  Miers' 
  Catalogue 
  of 
  the 
  New 
  Zealand 
  Crustacea 
  in 
  the 
  

   British 
  Museum, 
  our 
  knowledge 
  of 
  the 
  whole 
  class 
  was 
  fragmentary 
  and 
  

   scattered 
  throughout 
  numerous 
  works. 
  Now, 
  however, 
  that 
  all 
  the 
  infor- 
  

   mation 
  on 
  the 
  subject 
  has 
  been 
  thus 
  collected 
  and 
  published 
  in 
  a 
  condensed 
  

   form, 
  it 
  becomes 
  more 
  easy 
  to 
  fill 
  up 
  the 
  existing 
  gaps. 
  

  

  The 
  Entomostraca 
  are 
  an 
  interesting 
  and 
  but 
  little 
  studied 
  division 
  of 
  

   Crustaceans, 
  and 
  from 
  then- 
  abundance 
  are 
  of 
  considerable 
  importance. 
  

   The 
  species 
  enumerated 
  here 
  have 
  been 
  collected 
  chiefly 
  within 
  a 
  few 
  miles 
  

   of 
  Duuediu, 
  and 
  the 
  marine 
  forms 
  only 
  between 
  tide 
  marks 
  ; 
  so 
  that 
  we 
  are 
  

   as 
  yet 
  only 
  on 
  the 
  threshold 
  of 
  the 
  subject. 
  

  

  