﻿G4 
  A 
  MONOGRAPH 
  OF 
  THE 
  VICTORIAN 
  SPONGES. 
  

  

  described 
  on 
  p. 
  34. 
  The 
  developing 
  embryos 
  are 
  contained 
  in 
  separate 
  spherical 
  

   cavities 
  hned 
  by 
  very 
  large, 
  polygonal, 
  plate-like 
  cells 
  (PI. 
  VII., 
  Fig. 
  3). 
  

  

  (d.) 
  Arrangement 
  of 
  the 
  Skeleton.— 
  Ti\(i 
  skeleton 
  consists 
  of 
  triradiate 
  spicules 
  

   only, 
  arranged 
  as 
  usual 
  in 
  the 
  thickness 
  of 
  the 
  mesoderm 
  and 
  often, 
  especially 
  in 
  the 
  

   thick 
  pseudoderm, 
  in 
  several 
  layers. 
  

  

  (f.) 
  The 
  Spicules 
  (PI. 
  XL, 
  Fig. 
  ?>).— 
  Dermal. 
  Eegular 
  triradiates 
  ; 
  rays 
  stout, 
  

   conical, 
  gradually 
  sharp-pointed, 
  measuring 
  about 
  0.14 
  by 
  0.014 
  mm., 
  or 
  a 
  

   trifle 
  stouter. 
  Deep. 
  Like 
  the 
  derinal 
  spicules 
  but 
  with 
  the 
  rays 
  a 
  little 
  shorter 
  

   and 
  slenderer, 
  still 
  fairly 
  stout. 
  

  

  {d.) 
  Affinities. 
  — 
  This 
  species 
  obviously 
  comes 
  very 
  near 
  to 
  Haeckel's 
  Ascetta 
  

   primordialis 
  var. 
  loculosa* 
  but 
  it 
  is 
  no 
  easy 
  matter 
  to 
  determine 
  what 
  Ascetta 
  

   primordialis 
  var. 
  locidosa 
  really 
  is, 
  as 
  the 
  name 
  is 
  evidently 
  applied 
  by 
  Haeckel 
  to 
  a 
  

   number 
  of 
  forms 
  which 
  differ 
  widely 
  in 
  canal 
  system 
  and 
  nnist 
  therefore, 
  according 
  

   to 
  our 
  view, 
  be 
  considered 
  as 
  distinct 
  species. 
  

  

  Ascetta 
  lociilosa, 
  H. 
  (Ascetta 
  primordialis 
  var. 
  loculosa) 
  is 
  diagnosed 
  by 
  Hseckel 
  as 
  

  

  follows: 
  " 
  Spicula 
  alle 
  von 
  gleicher 
  Grosse, 
  einer 
  doppelte 
  oder 
  mehrfache 
  Schicht 
  

  

  im 
  Exoderm 
  bildend, 
  ihre 
  Strahlen 
  8-16 
  mal 
  so 
  lang 
  als 
  dick. 
  Entoderm 
  verdickt, 
  

   ein 
  geschichtetes 
  Epithelium 
  bildend, 
  welches 
  durch 
  blattformige 
  Fortsatze 
  oder 
  

   Septa 
  die 
  Darmhohle 
  in 
  Facher 
  abtheilt. 
  (Australienf' 
  As 
  it 
  is 
  placed 
  in 
  the 
  genus 
  

   Ascetta 
  the 
  spicules 
  are, 
  of 
  course, 
  all 
  triradiate. 
  The 
  only 
  further 
  description 
  given 
  

   by 
  Hffickel 
  of 
  the 
  remarkable 
  species 
  or 
  variety 
  loculosa 
  is 
  as 
  follows 
  : 
  — 
  " 
  Eine 
  andere 
  

   sehr 
  bemerkenswerthe 
  Varietiit, 
  die 
  ich 
  anfangs 
  fur 
  eine 
  ganz 
  verschiedene 
  Art 
  hielt, 
  

   bekam 
  ich 
  aus 
  Siidaustralien 
  (Ascetta 
  loculosa). 
  Hier 
  war 
  sowohl 
  Exoderm 
  als 
  

   Entoderm 
  verdickt. 
  Das 
  Exoderm 
  enthielt 
  mehrfache 
  Nadelschichten 
  und 
  bildete 
  

   diinne 
  membranoese 
  Vorspriinge 
  und 
  Scheidewande 
  inneshalb 
  der 
  Darmrdhren, 
  

   durch 
  welche 
  dieselben 
  in 
  Facher 
  abgetheilt 
  wurden. 
  Diese 
  Scheidewande 
  enthielten 
  

   keine 
  Spicula 
  und 
  trugen 
  ein 
  aus 
  mehreren 
  Schichten 
  von 
  Epithelzellen 
  gebildetes 
  

   Entoderm. 
  Bei 
  einigen 
  Stocken 
  fand 
  sich 
  in 
  jedeni 
  Fach 
  ein 
  reifer 
  Embryo, 
  ganz 
  

   ahnlich 
  wie 
  bei 
  Ascetta 
  clathrus, 
  wo 
  dies 
  Verhaltniss 
  genauer 
  beschrieben 
  werden 
  wird 
  

   (vgl. 
  Taf. 
  4, 
  Fig. 
  4-7). 
  Die 
  Stocke 
  von 
  Ascetta 
  loculosa, 
  welche 
  solche 
  Facher 
  in 
  der 
  

   Darmhohle 
  enthielten, 
  wurden 
  im 
  klinstlichen 
  System 
  zu 
  vier 
  verschiedenen 
  

   Gattungen 
  gehort 
  haben, 
  namlich 
  Soleniscus, 
  Tarrus, 
  Auloplegma 
  und 
  Ascometra." 
  

  

  Probably 
  our 
  Leucosolenia 
  wilsoni 
  is 
  identical 
  with 
  one 
  or 
  other 
  of 
  the 
  forms 
  

   included 
  by 
  Hoeckel 
  under 
  the 
  name 
  Ascetta 
  loculosa, 
  although 
  without 
  more 
  exact 
  

   information 
  as 
  to 
  the 
  latter 
  it 
  is 
  difficult 
  to 
  be 
  certain 
  of 
  this. 
  But, 
  granting 
  that 
  it 
  

   is 
  so, 
  the 
  question 
  of 
  nomenclature 
  is 
  still 
  by 
  no 
  means 
  settled, 
  as 
  we 
  have 
  to 
  decide 
  

  

  • 
  "Die 
  Kalkschwiimme," 
  Vol. 
  II., 
  pp. 
  17, 
  23. 
  

  

  