﻿628 
  COLLECTIONS 
  FEOM 
  THE 
  WESTEEN 
  INDIAN 
  OCEAN. 
  

  

  CALCAREA. 
  

  

  No 
  Calcarea 
  from 
  this 
  district 
  are 
  recorded 
  in 
  Hackel's 
  ' 
  Kalk- 
  

   scliwamme' 
  (1872); 
  but 
  SchufFner 
  (Jenaisch. 
  Zeitsch. 
  xi.) 
  in 
  1878 
  

   described 
  several 
  species 
  from 
  Mauritius, 
  where 
  they 
  were 
  collected 
  

   by 
  Prof. 
  Mobius. 
  

  

  LEUCONIDtE. 
  

  

  Two 
  very 
  widely 
  distributed 
  known 
  species, 
  a 
  second 
  species 
  

   added 
  to 
  a 
  hitherto 
  monotypic 
  genus 
  (Leucortis), 
  and 
  a 
  known 
  

   Mascarene 
  species, 
  all 
  belonging 
  to 
  the 
  Leuconida), 
  represent 
  in 
  this 
  

   collection 
  the 
  Calcarea 
  of 
  the 
  Western 
  part 
  of 
  the 
  Indian 
  Ocean. 
  

  

  53. 
  Leucetta 
  primigenia, 
  var. 
  megalirrhaphis. 
  

  

  Leucetta 
  primigenia, 
  var. 
  megaraphis, 
  Hdckel, 
  KalkscMvamme, 
  ii. 
  

   p. 
  118. 
  

  

  Two 
  subglobular 
  specimens 
  9 
  and 
  18 
  millim. 
  in 
  diameter, 
  re- 
  

   spectively, 
  of 
  the 
  Dyssycus-ioTTo.. 
  Colour 
  in 
  spirit 
  pale 
  brown. 
  

   Hiickel 
  states 
  that 
  this 
  variety 
  is 
  rare, 
  but 
  does 
  not 
  give 
  localities. 
  

   In 
  the 
  specimen 
  which 
  I 
  examined, 
  the 
  small 
  triradiates 
  are 
  chiefly 
  

   confiried 
  to 
  a 
  thin 
  cortical 
  layer. 
  

  

  Hah. 
  SeycheUe 
  Islands, 
  12 
  fms. 
  

  

  Distribution 
  of 
  species. 
  Almost 
  cosmopolitan. 
  

  

  54. 
  Lencaltis 
  bathybia, 
  Hdckel, 
  var. 
  mascarenica, 
  nov. 
  

   (Plate 
  LIY. 
  figs, 
  a, 
  a'.) 
  

   Kalkschwdmme, 
  ii. 
  p. 
  156, 
  pi. 
  xxviii. 
  fig. 
  2. 
  

  

  Some 
  specimens 
  of 
  the 
  Ami?horiscus-iorm., 
  composed 
  of 
  branching 
  

   and 
  anastomosing 
  tubes, 
  cylindrical 
  or 
  somewhat 
  compressed, 
  2*5 
  

   to 
  3'5 
  millim. 
  in 
  diameter 
  ; 
  lumen 
  1-5 
  to 
  2*5 
  millim. 
  wide, 
  wall 
  

   about 
  "5 
  miUim. 
  thick. 
  Colour 
  duU 
  umber-brown 
  to 
  cream-colour. 
  

   The 
  large 
  quadriradiates 
  are 
  very 
  large, 
  viz. 
  rays 
  about 
  '07 
  millim. 
  

   thick, 
  and 
  rather 
  short, 
  with 
  a 
  long 
  apical 
  ray 
  projecting 
  into 
  the 
  

   cloacal 
  cavity, 
  and 
  frequently 
  a 
  basal 
  in 
  the 
  same 
  plane 
  but 
  opposite 
  

   to 
  the 
  apical 
  ; 
  the 
  small 
  triradiates 
  and 
  quadriradiates 
  are 
  very 
  small, 
  

   viz. 
  rays 
  about 
  "007 
  millim. 
  thick, 
  and 
  most 
  commonly 
  have 
  the 
  

   forms 
  figured 
  in 
  figs. 
  2 
  c, 
  2, 
  d 
  of 
  Hackel's 
  plate 
  (I. 
  c), 
  viz. 
  with 
  very 
  

   large 
  facial 
  angle. 
  The 
  larger 
  triradiates 
  are 
  usually 
  regular, 
  and 
  

   their 
  rays 
  are 
  about 
  "04 
  millim. 
  in 
  diameter. 
  The 
  slight 
  thickness 
  

   of 
  the 
  body- 
  wall, 
  the 
  proportions 
  of 
  the 
  spicules, 
  and 
  the 
  general 
  

   form 
  of 
  the 
  specimens 
  (which 
  is 
  simply 
  cylindrical 
  in 
  Hackel's 
  

   specimens) 
  distinguish 
  this 
  form 
  from 
  varr. 
  perimina 
  and 
  arabica, 
  

   Hackel 
  ; 
  but 
  in 
  the 
  straight 
  or 
  but 
  slightly 
  curved 
  spicular 
  rays 
  it 
  

   approaches 
  most 
  closely 
  the 
  latter 
  variety. 
  

  

  Hah. 
  Darros 
  Island, 
  Amiranto 
  group; 
  SeycheUe 
  Islands, 
  4-12 
  fms. 
  

  

  Distribution 
  of 
  species. 
  Red 
  Sea 
  (Bdchel) 
  ; 
  Port 
  Jackson 
  (Part 
  I., 
  

   p. 
  482, 
  of 
  this 
  Report). 
  

  

  