There are about 9,000 species of sponges. they all differ in size less than a centimeter to a mass that would fill one's arm. (Miller/Harley, Zoology,1996)
Commonly known as sponge
Asymmetrical or rdially symmetrical
Three cell type: pinacocytes, mesenchyme, and choanocytes
Has a central cavity or series of branching chambers, through which water passes through.
has no tissues or any organs.
The way the sponge filter and circulate water defines its form. Sponges have three known forms.
Ascon: vaselike form
Sycon: folded form
Leucon: Branch form