Am.  Jour.  Pharm. ") 
May,  1887.  j 
Bahama  Sponges. 
259 
these  can  be  closed  at  the  will  of  the  animal.  A  current  of  water 
carrying  food  to  the  animal  enters  through  the  smaller  openings,  and 
is  subsequently  ejected  through  the  larger  openings  or  oscules.  This 
current  is  set  up  by  means  of  specially  ciliated  sponge  particles  con- 
tained in  cavities  below  the  surface  of  the  sponge,  the  cilia  waving  in 
one  direction  only,  like  those  of  the  mucous  membrane  of  the  lungs  in 
higher  animals ;  the  ordinary  particles  of  the  sponge  flesh  possessing 
no  cilia,  but  having  only  an  amoeboid  movement.  The  openings  in 
the  gelatinous  surface  correspond  to  the  openings  visible  in  the  horny 
skeleton,  and  it  is  by  the  character  and  the  arrangement  of  these,  as 
well  as  by  that  of  the  fibres,  that  sponges  are  classified  both  commer- 
cially and  scientifically. 
Until  the  discovery  of  sponges  in  the  Bahamas  and  in  the  vicinity 
of  Florida,  all  the  sponges  of  commerce  were  derived  from  the  east- 
ern half  of  the  Mediterranean  sea,  which  still  supplies  the  finest  quali- 
ties. A  great  number  of  varieties,  both  in  form  and  relative  degrees 
of  softness  or  hardness,  are  recognized;  one  London  sponge  merchant 
even  asserting  that  there  are  as  many  as  four  hundred  Mediterranean 
kinds.  These  varieties,  whether  of  European  or  American  origin, 
are  referred  by  zoologists  to  three  principal  types : — 
1.  Spongia  officinalis,  L.,  which  is  the  source  of  the  Turkey  cup 
sponge. 
2.  Spongia  agaricina,  Schmidt,  affording  a  cup  sponge  of  harder 
and  more  unyielding  texture  than  the  Turkey  cup  and  known  as  the 
Zimocca  sponge. 
3.  Spongia  equina,  Schmidt,  yielding  the  bath  or  honeycomb 
sponge. 
The  first,  according  to  Mr.  Saville  Kent,*  is  distinguished  by  its 
usually  cup-shaped  contour,  by  the  exceedingly  fine  elastic  and  densely 
interwoven  fibres  of  which  it  is  composed,  and  by  the  oscules  being 
more  crowded  towards  the  centre  of  the  cup. 
The  second,  or  Zimocca  sponge,  is  recognized  at  sight  from  the 
Turkey  cup  sponge — which  it  closely  resembles  in  shape,  although 
the  cups  are  flatter  and  more  saucer-shaped — by  the  fact  that  the 
larger  openings,  instead  of  being  crowded  towards  the  centre  of  the 
cup,  are  uniformly  scattered  at  nearly  regular  distances  over  its  whole 
upper  surface,  and  by  being  much  harder  and  more  unyielding  to  the 
*  "Report  on  the  Sponges  of  the  Bahama  Islands,"  by  W.  Saville  Kent,  p. 
407,  in  '  Fisheries  Exhibition  Literature,'  vol.  v.,  part  ii. 
