312 
DE.  j.  s.  boweebaxk:  on  the  anato:\it 
Dactylocalyx  pumicea,  intermingled  with  the  trifnrcato-attenuato-hexradiate  spicula,  and 
it  appears  to  be  even  more  abundant  than  the  last-named  fonn. 
Spinulo-quadrifurcate  hexradiate  stellate  (Plate  XXVI.  %.  2.). — rectangnlated 
hexradiate  spiculum,  having  each  primaiy  ray  terminating  in  four’  nearly  equidistant 
cylindro-spinulate  secondary  radii. 
These  spicula  occur  abundantly  in  a beautiful  and  unique  specimen  of  a cup-shaped 
siliceo-fibrous  sponge  in  the  cabinet  of  my  friend  Mr.  TnoiLts  Ixgall.  The  remains  of 
the  sarcode  are  crowded  with  them  in  a perfect  state  of  preservation.  The  specimen 
represented  by  figure  2 has  had  three  of  its  primary  radii  broken  off  near  then*  common 
base,  thus  enabling  us  to  see  distinctly  the  structure  of  this  curious  and  beautiful  form 
of  spiculum. 
Floricomo-hexradiate  (Plate  XXVI.  figs.  3 and  4). — The  central  radii  consist  of  six 
rectangnlated  primary  rays  of  equal  length,  with  slightly  expanded  terminations,  from 
each  of  which  there  issue  seven  or  more  petaloid  secondary  spicula,  the  whole  forming 
one  of  the  most  beautiful  simulations  of  a flower  imaginable. 
Each  petaloid  spiculum  is  slender  at  its  proximal  termination,  and  continues  to  be  so 
until  near  its  distal  end,  where  it  expands  laterally,  and  presents  a nearly  semicircular 
concavo-convex  termination,  with  a beautiful  dentate  mai*gin,  the  number  of  the  dents 
being  usually  seven.  Each  of  the  petaloid  spicula  curves  gently  outward  from  its  base, 
the  flowing  line  returning  towards  the  central  axis  of  the  flower  at  about  half  of  its 
height  from  the  base,  and  then  it  again  curves  outward,  until  the  apical  expansion  is  at 
right  angles  to  the  floral  axis ; so  that  the  whole  resolves  itself  into  a form  like  that  of 
the  flower  of  a Jasmin.  The  beautiful  terminal  petaloid  expansions,  ufith  theii-  regu- 
larly disposed  marginal  dents,  renders  the  illusion  complete;  the  united  basal  cuiwes 
looking  as  if  they  had  been  produced  by  the  swelling  ovarium  of  a flower. 
I have  obtained  a considerable  number  of  these  elegant  spicula  from  my  friend 
Mr.  Cuming’s  beautiful  specimen  of  Euplectella  aspergillum^  which,  uith  his  accustomed 
liberality,  he  placed  at  my  disposal  for  examination.  They  are  found  also  in  Dr.  A. 
Farre’s  specimen  of  Eaplectella,  agreeing  in  every  respect  with  those  from  Mr.  Cuming’s 
sponge. 
CoRONATO-HEXRADiATE  STELLATE  (Plate  XXVI.  fig.  6). — The  Central  radii  consist  of 
six  rectangulated  primary  rays  of  equal  length,  each  terminating  in  a discoid  expansion, 
the  margin  of  which  is  furnished  with  numerous  curved  petaloid  radii.  ' 
I obtained  this  beautiful  but  very  minute  spiculum  through  the  kindness  of  Professors  | 
Milne-Edwards  and  Valenciennes,  from  a specimen  of  EuplecteUa  in  the  Museum  of  | 
the  Jardin  des  Plantes,  Paris,  in  which  there  are  two  of  these  beautiful  sponges,  one 
being  in  a much  better  state  of  preservation  than  the  other,  and  in  tlie  mutilated  speci-  j 
men  this  beautiful  form  was  found.  I 
The  spiculum  is  evidently  not  in  a perfect  state  of  preservation,  as  there  are  only  foiu  j 
rays  out  of  the  six  present : but  at  the  centre  of  the  spiculum  there  is  the  indication  of 
the  former  existence  of  one  of  the  two  missing  radii.  The  coronal  terminations  are  very 
