While trying to find out the characteristic of a newly found animal, a researcher did the histology of an adult animal and observed a cavity with presence of mesodermal tissue towards the body wall but no mesodermal tissue was observed towards the alimentary canal. What could be the possible coelom of that animal?
- Schizocoelomate
- Spongocoelomate
- Acoelomate
- Pseudocoelomate
Answer
(4) Pseudocoelomate
Solution
As per NCERT, a body cavity lined by mesoderm is a true coelom (coelomates, e.g. annelids, chordates).
As per NCERT, in some animals the body cavity is not lined by mesoderm; the mesoderm is present only as scattered pouches between the ectoderm and the endoderm. Such a cavity is a pseudocoelom (pseudocoelomates, e.g. aschelminths).
Mesoderm is found towards the body wall but not around the alimentary canal, so the cavity is not fully lined by mesoderm.
The animal is a pseudocoelomate.
Acoelomates (e.g. platyhelminthes) have no body cavity at all, and schizocoelomates have a true coelom.
Answer: (4)