﻿398 
  COLLECTIONS 
  FROM 
  MELANKSIA. 
  

  

  here 
  few 
  in 
  number 
  and 
  reduced 
  in 
  dimensions 
  : 
  the 
  primary 
  fibres 
  

   are 
  more 
  slender 
  and 
  much 
  more 
  strongly 
  spicular, 
  and 
  I 
  have 
  not 
  

   observed 
  here 
  the 
  cylindrical 
  form 
  of 
  spicule 
  which 
  accompanies 
  the 
  

   acerate 
  in 
  G. 
  armigera 
  ; 
  the 
  vents 
  are 
  more 
  abundant 
  and 
  the 
  growth 
  

   is 
  repent, 
  instead 
  of 
  suberect. 
  Still 
  I 
  believe 
  the 
  species 
  to 
  be 
  not 
  

   remotely 
  allied 
  ; 
  and 
  this 
  near 
  relation 
  between 
  two 
  species, 
  one 
  of 
  

   which 
  has 
  an 
  aculeated 
  surface 
  and 
  an 
  erect 
  growth, 
  while 
  the 
  

   other 
  is 
  decumbent 
  and 
  scarcely 
  at 
  all 
  aculeated, 
  shows 
  how 
  little 
  

   value 
  for 
  the 
  group-distinction 
  of 
  the 
  Chalinidfe 
  such 
  characters 
  may 
  

   possess. 
  The 
  variation 
  shown 
  by 
  different 
  specimens 
  (see 
  descrip- 
  

   tion) 
  is 
  somewhat 
  wide. 
  

  

  26. 
  Cladoclialiiia 
  pergamentacea. 
  

  

  Cladochalina 
  armigera, 
  var. 
  pergamentacea 
  *, 
  Ridley, 
  P. 
  Z. 
  S. 
  1881, 
  

   p. 
  112, 
  pi. 
  X. 
  %. 
  4. 
  

  

  A 
  young 
  specimen 
  of 
  compressed 
  form, 
  smooth 
  surface, 
  and 
  with 
  

   a 
  row 
  of 
  vents 
  along 
  each 
  margin, 
  with 
  the 
  fibre 
  as 
  in 
  C. 
  armigera, 
  

   and 
  spicules 
  measuring 
  "09 
  by 
  -0016 
  millim. 
  and 
  shaped 
  like 
  those 
  

   of 
  C. 
  armigera, 
  seems 
  to 
  belong 
  to 
  the 
  above 
  form. 
  

  

  Hah. 
  Thursday 
  Island, 
  Torres 
  Straits, 
  3-4 
  fms. 
  (on 
  Retepora). 
  

  

  Distribution. 
  Hotspur 
  Bank, 
  off 
  S.E. 
  Brazil 
  (Hidley). 
  

  

  ACERYOCHALINA, 
  g. 
  n. 
  

  

  Chalina, 
  Schmidt, 
  Suppl. 
  ii. 
  Adr. 
  Meer. 
  p. 
  10 
  (iiec 
  Botverbank'). 
  

  

  Massive, 
  sessile 
  Chalinidae. 
  Fibre 
  strongly 
  ceratinous, 
  containing 
  

   axially 
  or 
  diff'usely 
  arranged 
  slender 
  acerate 
  spicules, 
  which 
  do 
  not 
  

   exceed 
  in 
  bulk 
  the 
  horny 
  material 
  of 
  the 
  fibre 
  which 
  contains 
  them. 
  

   Vents 
  distinct, 
  ranged 
  along 
  upper 
  surface. 
  

  

  Type 
  Chalina 
  limbata, 
  Bowerbank 
  (Mou. 
  Brit. 
  Spong. 
  ii. 
  p. 
  373 
  ; 
  

   ? 
  Montagu). 
  

  

  This 
  genus 
  appears 
  to 
  be 
  most 
  closely 
  allied 
  to 
  Cladochalina, 
  by 
  

   its 
  strong 
  relative 
  development 
  of 
  keratose, 
  its 
  fine 
  acerate 
  spicules, 
  

   and 
  its 
  serial 
  vents. 
  Mr. 
  Carter 
  indicated 
  the 
  distinctness 
  of 
  such 
  

   forms 
  as 
  long 
  ago 
  as 
  1875, 
  when 
  (Ann. 
  & 
  Mag. 
  N. 
  H. 
  (4) 
  xvi. 
  pp. 
  142, 
  

   162) 
  he 
  established 
  the 
  family 
  Acervochalinida, 
  making 
  his 
  first 
  

   group 
  of 
  the 
  family 
  Solida, 
  in 
  which 
  Acervochalina 
  would 
  come. 
  

   He 
  himself 
  suggested 
  the 
  name 
  which 
  I 
  have 
  adopted, 
  and 
  has 
  

   sent 
  me 
  a 
  specimen 
  illustrating 
  his 
  view 
  of 
  the 
  species 
  which 
  should 
  

   be 
  assigned 
  to 
  the 
  genus. 
  The 
  constancy 
  in 
  form 
  of 
  both 
  this 
  and 
  

   the 
  following 
  species, 
  and 
  their 
  agreement 
  in 
  other 
  points, 
  show 
  them 
  

   to 
  be 
  no 
  mere 
  dwarfed 
  forms 
  of 
  erect 
  Chalinidte. 
  

  

  Schmidt 
  has 
  on 
  reconsideration 
  (Atl. 
  Geb. 
  p. 
  38) 
  referred 
  Chalina 
  

   limbata 
  to 
  Chalinula 
  ; 
  but 
  that 
  genus 
  is 
  equivalent 
  to 
  Chalina, 
  

  

  * 
  This 
  so-called 
  variety 
  seems, 
  by 
  the 
  constancy 
  of 
  the 
  peculiarities 
  of 
  its 
  

   external 
  form, 
  tIz. 
  knife-like 
  shape, 
  two 
  marginal 
  rows 
  of 
  vents, 
  and 
  smooth 
  

   surface, 
  to 
  differ 
  specifically 
  from 
  C. 
  armigera, 
  and 
  may 
  therefore 
  stand 
  as 
  

   Cladochalina 
  pergamentacea. 
  

  

  