﻿78 
  Mr. 
  A. 
  Deudy 
  on 
  Sponges 
  from 
  

  

  oxeote 
  to 
  strongylote 
  ; 
  they 
  vary 
  much 
  in 
  size, 
  especially 
  in 
  

   diameter, 
  the 
  average 
  measurements 
  of 
  a 
  full-grown 
  spicule 
  

   being 
  about 
  0*37 
  by 
  0*0175 
  millim. 
  

  

  My 
  examination 
  of 
  a 
  very 
  fine 
  series 
  of 
  specimens 
  in 
  the 
  

   British 
  Museum 
  has 
  shown 
  me 
  that 
  the 
  spiculation 
  of 
  this 
  

   species 
  varies 
  considerably 
  ; 
  but 
  I 
  know 
  of 
  no 
  tangible 
  

   characters 
  whereby 
  the 
  different 
  varieties 
  can 
  be 
  separated. 
  

  

  The 
  specimen 
  collected 
  by 
  Dr. 
  Anderson 
  in 
  the 
  Mergui 
  

   Archipelago 
  (fig. 
  2) 
  resembles 
  Mr. 
  Thurston's 
  specimen 
  in 
  

   texture 
  and 
  cup-like 
  shape 
  ; 
  but 
  the 
  surface-ridges 
  are 
  much 
  

   more 
  jagged 
  and 
  irregular 
  and 
  the 
  spicules 
  are 
  rather 
  larger. 
  

   Ridley's 
  cup-shaped 
  specimen 
  from 
  the 
  ' 
  Alert 
  ' 
  collection 
  

   differs 
  in 
  its 
  thin 
  walls, 
  tougher 
  texture, 
  and 
  small 
  size, 
  but 
  

   agrees 
  pretty 
  well 
  in 
  spiculation. 
  

  

  Lamarck 
  says 
  of 
  his 
  specimen 
  : 
  — 
  " 
  Cet 
  alcyon 
  forme 
  une 
  

   plaque 
  elliptique, 
  un 
  peu 
  convexe 
  en 
  dessus, 
  concave 
  en 
  des- 
  

   sous 
  comme 
  s'il 
  s'e'toit 
  moule 
  sur 
  le 
  dos 
  de 
  quelque 
  crabe, 
  et 
  

   rappelle 
  la 
  forme 
  de 
  la 
  carapace 
  superieure 
  d'une 
  tortue. 
  

   Probably 
  his 
  specimen 
  was 
  only 
  a 
  fragment 
  of 
  the 
  side 
  of 
  a 
  

   cup. 
  The 
  fragment 
  in 
  the 
  British 
  Museum, 
  purporting 
  to 
  

   come 
  from 
  Lamarck's 
  collection, 
  agrees 
  very 
  well 
  in 
  general 
  

   appearance 
  with 
  our 
  present 
  specimen, 
  so 
  far, 
  of 
  course, 
  as 
  

   can 
  be 
  judged 
  from 
  a 
  small 
  piece 
  ; 
  the 
  spicules 
  measure 
  047 
  

   by 
  0*017 
  millim. 
  and 
  have 
  well-rounded 
  ends. 
  

  

  Reniera 
  madrepora, 
  n. 
  sp. 
  (PL 
  IV. 
  fig. 
  9.) 
  

  

  The 
  single 
  specimen 
  in 
  the 
  collection 
  is 
  bushily 
  ramose 
  ; 
  

   it 
  branches 
  very 
  freely, 
  and 
  the 
  branches 
  are 
  short, 
  subcylin- 
  

   drical 
  or 
  somewhat 
  flattened, 
  and 
  often 
  anastomose. 
  The 
  

   branching 
  shows 
  a 
  decided 
  tendency 
  to 
  become 
  palmate 
  and 
  

   there 
  is 
  a 
  short 
  stout 
  pedicel. 
  The 
  height 
  of 
  the 
  specimen 
  is 
  

   150 
  millim. 
  and 
  the 
  greatest 
  breadth 
  a 
  little 
  more 
  ; 
  the 
  average 
  

   diameter 
  of 
  the 
  branches 
  is 
  about 
  8 
  millim. 
  The 
  oscula 
  are 
  

   small 
  and 
  scattered, 
  chiefly 
  on 
  the 
  inwardly-turned 
  faces 
  of 
  

   the 
  branches. 
  The 
  surface 
  in 
  the 
  dry 
  state 
  is 
  minutely 
  

   hispid, 
  the 
  texture 
  rather 
  hard 
  but 
  brittle, 
  and 
  the 
  colour 
  

   dull 
  orange. 
  No 
  record 
  was 
  kept 
  of 
  the 
  colour 
  in 
  the 
  living 
  

   state. 
  

  

  The 
  skeleton 
  is 
  arranged 
  in 
  the 
  rectangular 
  manner 
  charac- 
  

   teristic 
  of 
  the 
  genus, 
  with 
  obvious 
  distinction 
  into 
  primary 
  

   and 
  secondary 
  fibres 
  ; 
  but 
  it 
  is 
  irregular, 
  and, 
  though 
  dense, 
  

   the 
  spicules 
  are 
  loosely 
  bound 
  together 
  and 
  may 
  occur 
  scat- 
  

   tered 
  outside 
  the 
  true 
  primary 
  and 
  secondary 
  lines 
  of 
  the 
  

   skeleton. 
  In 
  the 
  centre 
  of 
  the 
  branches 
  the 
  skeleton 
  becomes 
  

  

  