The phylum name Porifera means pore-bearing. Sponges take their name from small holes that cover their bodies.

1. PORIFERA
DR.V.JEYANTHI KUMARI
ASSISTANT PROFESSOR OF ZOOLOGY
A.P.C.MAHALAXMI COLLEGE FOR WOMEN
THOOTHUKUDI-628002

2. Phylum porifera is divided into 3 classes based on types of
spicules. They are
1.CALCAREA
2.HEXA’ACTI’NELLIDA &
3.Demospongia.

3. CALCAREA
1.Skeleton is formed of
calcareous spicules
2.Radially symmetrical
animals
3.Choanocyte cells are large
and conspicuous (easily
seen or notice)
4.They have usually a single
cavity called spongocoel
opening to the exterior
through a single opening
called osculum. Example
Clathrina, Leucosolenia.

5. HEXACTINELLIDA
1.Skeleton is formed of six
rayed triaxon, silicius
spicules.
2.Canal system is
branched or
unbranched
3.Radially symmetrical
4.These are also known as
glass sponges.
Examples Farrea,
Euplectella

7. DEMOSPONGIA
1.Skeleton either absent or
present.
2.If it has skeleton, it is
formed of spongin fibres
or combination of
spongin fibres and
silicious spicules.
3.The canal system is
complicated Rhagon type
4.These sponges are of
great economic
importance.
5.Ex. Spongilla, Cliona