AOT> PHYSIOLOGY OF THE SPONGIAD^. 
827 
and forming the areas for the support of the valvular terminations of the inter- 
marginal cavities, X 50 linear: page 788. 
Fig. 4. Four groups of inhalant pores in the dermal membrane, situated immediately 
above the distal ends of the intermarginal cavities of G. Barretti, X 83 linear : 
page 794. 
Fig. 5. A portion of the dermal surface of Halichondria panicea^ Johxston, showing the 
multispicular network for the support of the dermal membrane, and the open 
pores in the areas, X 108 linear: page 793. 
Fig. 6. A small portion of the dermal membrane from Bictyocylindrus stuposiis^ Bowee- 
BAJfK, MS., exhibiting the number and position of the minute sphero-stellate 
defensive spicula with which it is armed, X 308 linear: page 793. 
Fig. 7. A small portion of the quadrilateral siliceo-fibrous network of the dermis of the 
sponge upon which Dr. A. Faeee’s specimen of Euplectella cucumer^ Owen, 
is based, showing the double series of entirely spined spicular organs pro- 
jected from its angles, X 108 linear: page 790. 
Fig. 8. A small portion of the single-seried dermal spicular network of Isodictya varians, 
Boweebank, ms., X 108 linear: page 792. 
Fig. 9. A piece of reticulated kerato-fibrous tissue, for the support of the dermal mem- 
brane of one of the species of the common West Indian sponges of com- 
merce, X 108 linear: page 792. 
PLATE XXXIII. 
Fig. I. A longitudinal section of the intermarginal cavities of Grantia com^vessa, show- 
ing the cilia and their basal cells in situ, X 500 linear : page 806. 
Fig. 2. A view of a small portion of the inner surface of Grantia compressa, exhibiting 
the oscula open, and the appearance presented at their orifices by the cilia 
within in action, x 500 linear: page 806. 
Fig. 3. Two detached tessellated cells and their cilia, {a) in the position of inaction, 
{b) in the position of action, X 1250 linear: page 806, 
Fig. 4. A group of detached tessellated cells from the interior of the intermarginal 
cavities of Grantia compressa, X 1250 linear: page 807. 
Fig. 5. An ovarium of Spongilla Jluviatilis in its natural state, exhibiting the foramen, 
X 83 linear : page 808. 
Fig. 6. A small piece of a fibre of the skeleton of one of the common Bahama sponges 
of commerce, with numerous ova imbedded in its surface, X 400 linear: 
page 809. 
Fig. 7. A small piece of the fibre represented by fig. 6, exhibiting the varieties in form 
and proportion of the ova, X 1250 linear : page 809. 
Fig. 8. View of a section at right angles to the surface of a fragment of the skeleton of 
the ovarium of Spongilla flumatilis, prepared with nitric acid, exhibiting the 
MDCCCLXII. 5 u 
