AND  PHYSIOLOGY  OF  THE  SPONGIAD^. 
327 
Fig.  37.  Foliato-peltate,,  a side  view  of  a spiculum,  exhibiting  the  form  and  compara- 
tive length  of  the  shaft,  X 160  linear:  page  299. 
Fig.  38.  Foliato-peltate,  a fragment  exhibiting  furcated  terminations  to  two  out  of  the 
three  radiating  canals,  X 260  linear:  page  299. 
Retentive  Spicula. 
Fig.  39.  Simple  BiHiAMATE,  from  Halichondria  variantia,  Bowerbank,  MS.  British, 
Xl060  linear:  page  300. 
Fig.  40.  Eeversed  bihamate,  from  Halichondria  incrustans,  Johnston,  x 1066  linear : 
page  300. 
Fig.  41.  Contort  bihamate,  from  Halichondria  incrustans^  Johnston,  x1066  linear: 
page  300. 
Fig.  42.  Abbreviated  bihamate,  from  an  unknown  sponge,  X 1060  linear : page  301. 
Fig.  43.  Deflected  bihajviate,  from  the  spongeous  mass  at  the  base  of  Euplectella 
ciicumer,  Owen,  x660  linear:  page  301. 
Fig.  44.  Exter-umbonate,  from  an  undescribed  sponge  from  Sicily,  X 1060  linear : 
page  301. 
Fig.  45.  Inter-umbonate,  from  the  same  sponge  as  fig.  44,  X 1060  linear:  page  301. 
Fig.  46.  Bi-embonate,  from  the  same  sponge  as  fig.  44,  X 1060  linear:  page  301. 
Figs.  47,  48  and  49.  Clavated  bihamate,  from  the  same  sponge  as  fig.  44,  X 1060  linear; 
page  302. 
Fig.  50.  Unipocillated  bihamate,  from  Halichondria  Hyndmani,  Bowerbank,  MS., 
Xl060  linear:  page  302. 
Fig.  51.  Simple  bipocillated  bihamate,  from  Halichondria  Hyndmani,  Bowerbank,  MS., 
X 1060  linear:  page  302. 
Fig.  52.  Contort  bipocillated  bihamate,  from  Halichondria  Hyndmani,  Bowerbank, 
MS.,  xl060  linear:  page  302. 
Fig.  53.  Umbonated  bipocillated  bihamate,  from  Halicho7idria  Hyndmani,  Bowerbank, 
MS.,  X 1060  linear:  page  303. 
Fig.  54.  A view  in  profile  of  a unipocillated  spiculum,  illustrating  the  production  of 
the  umbo,  from  Halichondria  Hyndmani,  Bowerbank,  MS.,  xl060  linear: 
page  303. 
Fig.  55.  Bidentate  inequi-anciiorate,  from  an  undescribed  sponge  from  the  coast  of 
Sicily,  X 660  linear:  page  305. 
Fig.  56.  Palmated  inequi-anchorate,  from  an  undescribed  sponge,  X 660  linear : page 
305. 
Fig.  57.  Tridentate  EQUI-anchorate,  from  an  undescribed  sponge  in  the  cabinet  of 
Mr.  George  Shadbolt,  x 660  linear : page  305. 
Fig.  58.  Dentato-palmate  inequi-anchorate,  from  Spongia  lobata,  Montagu,  Isodictya 
lohata,  Bowerbank,  MS.,  xl060  linear:  page  306. 
MDCCCLVIII.  2 Y 
