Question
Biology Question on Kingdom Animalia
Choanocytes are seen in
A
Coelenterata
B
Porifera
C
Mollusca
D
Echinodermata.
Answer
Porifera
Explanation
Solution
The body wall of a common sponge (Phylum Porifera) consists of three layers:
(i) Pinacoderm (dermal layer) : It is outer cellular layer which consists of flattened pinacocytes and oval porocytes.
(ii) Choanoderm '(gastral layer) : It is inner cellular layer which consists of highly specialized flagellated cells called choanocytes (collar cells).
Both pinacoderm and choanoderm do not have basement membrane.
(iii) Mesohyl layer (mesenchyme): Basically, it is a noncellular layer found in between pinacoderm and choanoderm. It has fine dispersed spongin fibres and numerous spicules. It also ccmtai.ns amoebocytes (amoeba-like cells) of both pinacoderm and choanoderm.