Phylum Porifera

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)

General Characteristics

1. Commonly known as sponge

2. Asymmetrical or rdially symmetrical

3. Three cell type: pinacocytes, mesenchyme, and choanocytes

4. Has a central cavity or series of branching chambers, through which water passes through.

5. has no tissues or any organs.

Body Form

The way the sponge filter and circulate water defines its form. Sponges have three known forms.

1. Ascon: vaselike form

2. Sycon: folded form

3. Leucon: Branch form