400
Describe the location and function of each part in the sponge.
Osculum
Ostia
Spongin
Spicule
Osculum--Top, large hole in sponge, water exits here
Ostia--Side holes in sponge, water enters here
Spongin--Flexible protein only found in sponges, bulk of body wall, structure
Spicule--Hard, needlelike protein, provides "skeleton", support