Phylum Porifera are animals that are mainly marine, commonly known as sponges. They are multicellular invertebrates that lack definitive tissues. The 3 main types of cells are the flagellated choanocyte that helps circulate water, the amoebocytes that secrete spicules, and epidermal cells that are protective cells on the exterior.  The basic body plan is a sac with pores through which water circulates.  Three types of sponges that can be recognized by the type of spicules (reinforcing framework) they produce by cells called amoebocytes.  The spicules include: silica spicules in glass sponges, spongin spicules in bath sponges and calcium carbonate spicules in CaCO₃ sponges.

    Image 1 is a photo of the entire glass sponge.  Images 2 and 3 are top and bottom views of the glass sponge. Image 4 & 5 are the bath sponge examples seen in lab.  Image 6  is the calcium carbonate sponge.  Image 7 shows a close up view of the calcium carbonate sponge. Compare these sponges 1 - 7 (skeletal remains) to the living sponge in image 8.  Images 9 & 10 are not  sponge; they show the luffa which is a seed pod from the luffa vine.
 

1. entire glass sponge	2. top of glass sponge	3. bottom of glass sponge	4. bath          sponge	5. bath            sponge
6. CaCO3     sponge	7. enlarged CaCO3 sponge	8. living        sponge	9. entire     luffa	10. luffa      xs