This sponge is called the touch me not sponge becasue when it comes in contact with skin a severe allergic reaction occurs causing a rash, numbness, swelling and pain that can last several days. Sponges do not have cardiovascular systems but instead use a filtering system called a water based circulatory system that opens pores on the sponge called ostia that will create a current to draw water into the sponge so that it will reicieve oxygen from the water. In the ostias there are choanocyte that the water flows through and a flagellum at the end to keep the water moving and to catch any food. The water is then released through the top opening of the sponge called an osculum.