Members of this category 
Members of this category bear a strong resemblance to the colony-forming choanoflagellates, leading to the conjecture that they represent the jump from single to multi-cellular organisms. Aplysina red band syndrome is a disease that threatens members of this phylum in the Caribbean. They are divided into classes based on the type of spicules in their skeleton, and all members expel water through an opening called an osculum. FTP, identify this phylum with classes Calcarea and Demospongiae.
Members of this category bear a strong resemblance to the colony-forming choanoflagellates, leading to the conjecture that they represent the jump from single to multi-cellular organisms.
{porifera}