﻿244 
  Transaciinns. 
  — 
  Zoology. 
  

  

  The 
  young, 
  taken 
  from 
  the 
  incubatory 
  pouch 
  of 
  the 
  female, 
  differ 
  some- 
  

   what 
  from 
  the 
  adult. 
  The 
  back 
  is 
  smooth 
  and 
  rounded, 
  whereas 
  in 
  the 
  

   adult 
  it 
  is 
  sharply 
  keeled, 
  and 
  the 
  segments 
  of 
  the 
  pereion 
  are 
  produced 
  

   posteriorly 
  into 
  teeth. 
  The 
  pereion 
  is 
  very 
  broad 
  and 
  expanded. 
  Antennse 
  

   subequal; 
  superior 
  stout 
  and 
  conical, 
  three-jointed, 
  terminal 
  joint 
  with 
  a 
  

   few 
  short 
  setse 
  at 
  the 
  extremity 
  and 
  two 
  longer 
  ones 
  projecting 
  at 
  right 
  

   angles 
  from 
  near 
  the 
  middle 
  of 
  the 
  inferior 
  margin 
  ; 
  inferior 
  pair 
  somewhat 
  

   more 
  slender, 
  and 
  with 
  very 
  minute 
  sets. 
  Some 
  of 
  the 
  appendages 
  also 
  

   are 
  either 
  wanting 
  or 
  are 
  not 
  fully 
  developed, 
  probably 
  the 
  first 
  or 
  second 
  

   pair 
  of 
  gnathopoda. 
  Pieopoda 
  normally 
  developed. 
  

  

  These 
  minute 
  creatures 
  approach 
  in 
  form 
  and 
  general 
  appearance 
  to 
  

   Hyperia 
  cyanea 
  much 
  more 
  than 
  Themisio. 
  Every 
  adult 
  female 
  had 
  several 
  

   of 
  them 
  in 
  the 
  incubatory 
  pouch 
  under 
  the 
  pereion. 
  

  

  Frequently 
  washed 
  up 
  on 
  Ocean 
  Beach, 
  Dunedin. 
  

  

  Fam. 
  III. 
  Platyscelidse. 
  

   Cephalon 
  round. 
  Eyes 
  large. 
  Antennae 
  attached 
  to 
  the 
  inferior 
  surface. 
  

   Epistoma 
  proboscidiform 
  ; 
  oral 
  appendages 
  rudimentary. 
  Gnathopoda 
  

   complexly 
  subchelate. 
  First 
  two 
  pairs 
  of 
  pereiopoda 
  simple 
  ; 
  two 
  succeed- 
  

   ing 
  pairs 
  having 
  the 
  basa 
  largely 
  dilated 
  ; 
  fifth 
  pair 
  imperfectly 
  developed. 
  

   Posterior 
  pieopoda 
  fohaceous. 
  

  

  Genus 
  Platyscelus, 
  Spence 
  Bate, 
  

   Brit. 
  Mus. 
  Cat. 
  Amphip. 
  Crust., 
  p. 
  329. 
  

   Cephalon 
  transversely 
  ovate. 
  Pereion 
  distended 
  ; 
  first 
  segment 
  narrower 
  

   than 
  the 
  cephalon. 
  Pleon 
  much 
  narrower 
  than 
  the 
  pereion, 
  having 
  the 
  

   fourth 
  and 
  fifth 
  segments 
  coalescing, 
  the 
  fifth 
  and 
  sixth 
  pairs 
  of 
  pieopoda 
  

   being 
  attached 
  to 
  the 
  posterior 
  margin 
  ; 
  sixth 
  segment 
  and 
  telson 
  fused 
  

   together, 
  the 
  posterior 
  pair 
  of 
  pieopoda 
  being 
  attached 
  to 
  the 
  under 
  surface 
  

   near 
  the 
  middle 
  of 
  the 
  segment. 
  Superior 
  antenna 
  short, 
  consisting 
  of 
  a 
  

   peduncle 
  and 
  a 
  flagellum. 
  Inferior 
  antennae 
  not 
  longer 
  than 
  the 
  cephalon, 
  

   consisting 
  of 
  four 
  joints, 
  concealed 
  beneath 
  the 
  cephalon, 
  not 
  folded. 
  

   Mandibles 
  without 
  an 
  appendage. 
  Third 
  pair 
  of 
  pereiopoda 
  having 
  the 
  

   bases 
  largely 
  dilated, 
  and 
  the 
  remaining 
  joints 
  shorter 
  than 
  the 
  bases 
  ; 
  

   fourth 
  pair 
  having 
  the 
  bases 
  twice 
  as 
  large 
  as 
  the 
  third, 
  the 
  remaining 
  

   joints 
  not 
  half 
  so 
  long 
  as 
  the 
  basos 
  ; 
  fifth 
  pair 
  membranous, 
  a 
  small 
  

   tubercle 
  representing 
  the 
  remaining 
  joints. 
  Three 
  posterior 
  pairs 
  of 
  

   pieopoda 
  bhamous, 
  foliaceous, 
  submembranous. 
  Telson 
  obtusely 
  triano-ular. 
  

   20. 
  Platyscelus 
  inter 
  meclius, 
  nov. 
  sp. 
  Fig. 
  D.4. 
  

  

  Cephalon 
  rounded 
  in 
  front. 
  First 
  two 
  segments 
  of 
  pereion 
  very 
  narrow 
  ; 
  

   succeeding 
  broader, 
  subequal. 
  Eyes 
  very 
  large, 
  occupying 
  nearly 
  the 
  whole 
  

   cephalon, 
  with 
  a 
  large 
  triangular 
  red 
  pigment 
  spot 
  on 
  the 
  outside 
  of 
  each. 
  

   Epistoma 
  triangular. 
  Antennse 
  placed 
  quite 
  underneath 
  the 
  epistome. 
  

  

  