Body Plans of Sponges

Ascon

• choanocytes line spongocoel
  single osculum
• simplest body plan.
  

Sycon

• choanocytes lie in canals
• single osculum

Leucon

• most common
• branched canal system with choanocytes lying in small chambers

• multiple oscula

Taken from: http://yanuar66.blogspot.com/2012/03/kingdom-animalia.html