﻿ALCTONARIA, 
  331 
  

  

  Tcuconomii. 
  — 
  The 
  results 
  of 
  the 
  collection 
  in 
  this 
  respect 
  are 
  not 
  

   less 
  interesting 
  than 
  are 
  those 
  of 
  the 
  distrihution. 
  In 
  the 
  case 
  of 
  one 
  

   family 
  (the 
  Melitha3id;<>), 
  a 
  structural 
  character 
  has 
  for 
  the 
  first 
  time 
  

   come 
  to 
  light, 
  which 
  illustrates 
  the 
  existence 
  of 
  a 
  similar 
  character 
  

   in 
  other 
  families 
  of 
  this 
  natural 
  but 
  very 
  manifold 
  Order 
  : 
  I 
  refer 
  to 
  

   the 
  occurrence 
  of 
  two 
  kinds 
  of 
  zooids. 
  In 
  one 
  case 
  (in 
  the 
  same 
  

   family) 
  it 
  has 
  been 
  found 
  desirable 
  to 
  establish 
  a 
  new 
  genus, 
  and 
  the 
  

   number 
  of 
  new 
  species 
  is 
  relatively 
  large. 
  The 
  Melithteidte 
  show 
  a 
  

   remarkable 
  development 
  here. 
  A 
  remarkable 
  member 
  of 
  the 
  usually 
  

   rare 
  family 
  Briareida3 
  has 
  been 
  assigned 
  by 
  me 
  to 
  the 
  genus 
  Icili- 
  

   (jorgia, 
  hitherto 
  known 
  only 
  from 
  the 
  West 
  Indies. 
  The 
  number 
  of 
  

   species 
  of 
  this 
  family 
  found 
  here 
  is 
  relatively 
  large, 
  and 
  includes 
  

   some 
  rare 
  and 
  very 
  strange 
  forms 
  {Solenocdulum, 
  Leucoella). 
  Two 
  

   points 
  of 
  general 
  importance 
  for 
  the 
  family 
  Gorgoniidae 
  may 
  be 
  con- 
  

   sidered 
  to 
  have 
  been 
  decided 
  by 
  a 
  study 
  of 
  the 
  series 
  which 
  repre- 
  

   sents 
  the 
  new 
  species, 
  Lepto(jorgia 
  australiensis, 
  in 
  this 
  collection 
  — 
  

   1. 
  That 
  colour 
  alone 
  cannot 
  be 
  taken 
  as 
  a 
  character 
  of 
  specific 
  im- 
  

   portance. 
  2. 
  That 
  characters 
  derived 
  from 
  the 
  shape, 
  depth, 
  partial 
  

   presence 
  or 
  absence 
  of 
  superficial 
  grooves 
  in 
  the 
  cortex, 
  or 
  their 
  

   partial 
  rej^lacement 
  by 
  raised 
  lines, 
  as 
  seen 
  in 
  dry 
  specimens, 
  are 
  

   not 
  of 
  specific, 
  much 
  less 
  of 
  family 
  value, 
  as 
  held 
  by 
  Dr. 
  Gray 
  for 
  

   some 
  Gorgoniidae 
  (see 
  Catalogue 
  Lithoph, 
  Brit. 
  Mus., 
  p. 
  24, 
  Elli- 
  

   selladce). 
  

  

  Measurements 
  and 
  Terms 
  employed.— 
  The 
  measurements 
  of 
  spicules 
  

   are 
  those 
  of 
  average 
  greatest 
  specimens 
  of 
  each 
  form 
  of 
  spicule. 
  I 
  

   have 
  adopted 
  Yerrill's 
  term 
  verruca 
  to 
  signify 
  that 
  specialized 
  part 
  

   of 
  the 
  cortex 
  which 
  contains 
  the 
  retracted 
  zooid. 
  When 
  describing 
  

   them 
  I 
  have 
  applied 
  the 
  term 
  longitudinal 
  to 
  the 
  radiating 
  spicules 
  

   of 
  the 
  verruca, 
  and 
  liorizontal 
  to 
  those 
  which 
  are 
  circularly 
  arranged 
  

   with 
  regard 
  to 
  its 
  centre. 
  

  

  Classification. 
  — 
  I 
  have 
  followed 
  in 
  the 
  main 
  the 
  arrangement 
  

   adopted 
  by 
  Kolliker 
  in 
  his 
  ' 
  Icones 
  Histiologicae.' 
  

  

  ALCYO:^IIDJE. 
  

  

  Alctoniin^. 
  

  

  The 
  absence 
  of 
  both 
  Sarcophytum 
  and 
  Alcyonium 
  from 
  the 
  col- 
  

   lection 
  is 
  perhaps 
  due 
  to 
  the 
  absence 
  of 
  in-shore 
  reefs 
  in 
  the 
  area 
  

   examined. 
  An 
  Alcyonium 
  was 
  described 
  from 
  Port 
  King 
  George 
  in 
  

   Southern 
  Australia 
  by 
  Q,uoy 
  and 
  Gaimard 
  from 
  the 
  ' 
  Astrolabe 
  ' 
  

   voyage 
  ; 
  but 
  Lamarck's 
  A. 
  2^'"'tridosu7n, 
  from 
  that 
  locality, 
  I 
  have 
  

   ascertained 
  to 
  be 
  a 
  siliceous 
  Sponge. 
  

  

  