The Skeletal Structure
Their skeletons consist of fibers of the protein spongin and silica. Wherever silica's spike-like structures are found, they have a different shape than the similar glass sponges. There are two different skeleton architecture within this sponge: external and internal. External: Reticulation of isotropic,similar spicule tracts, surrounding large pores up to 200 micrometers across. Interior: Meshwork of spicule tracts, 30- 300 micrometers in diameter,outline rounded often cavernous meshes 120-1100 micrometers in diameter. Many loose spicule may be packed into dense masses that obscure the meshwork.