﻿PLATE 
  XX. 
  

  

  Willemcesia 
  leptodactyla 
  (p. 
  163). 
  

  

  Fig. 
  ]. 
  Pereioii, 
  with 
  lateral 
  wall 
  of 
  the 
  carapace 
  removed 
  to 
  .'^how 
  the 
  pfisition 
  and 
  

   arrangement 
  of 
  the 
  branchiae, 
  

  

  (". 
  Metope 
  or 
  facial 
  region, 
  showing 
  on 
  one 
  side 
  the 
  relative 
  positions 
  of 
  

  

  the 
  ophthalmopod 
  (a), 
  and 
  first 
  (h) 
  and 
  second 
  antennae 
  (c), 
  from 
  

   within. 
  

  

  r/, 
  d. 
  Siagones 
  or 
  mandibles 
  (the 
  synaphipod 
  should 
  have 
  only 
  two 
  joints). 
  

  

  d", 
  d". 
  Mctastomata. 
  

  

  /n«. 
  Cheiloglossa, 
  as 
  seen 
  between 
  the 
  mandibles. 
  

  

  vi. 
  Third 
  pair 
  of 
  pereiopoda 
  with 
  mastigobranchial 
  lash 
  and 
  podo- 
  

  

  branchial 
  plume. 
  

  

  ////". 
  One 
  of 
  the 
  hairs 
  and 
  spines 
  from 
  the 
  mastigobranchia 
  ; 
  enlarged. 
  

  

  III". 
  Section 
  of 
  a 
  podobranchial 
  plume. 
  

  

  ., 
  2. 
  (Jvuiu 
  enlarged, 
  showing 
  advanced 
  condition 
  of 
  the 
  embryo. 
  

  

  