Answer:
Nematodes are referred to as "pseudocoelomates" since their coelom is not entirely lined with mesoderm ally cell - derived in most forms, and they are triploblastic.
What is a nematode?
Any unsegmented worm of the phylum Nematoda, having an elongated, cylindrical body; a roundworm
What are characteristics of the pseudocoelomate phylum?
-bilateral symmetry, unsegmented, triploblastic
-body cavity a pseudocoel
-size: some microscopic, others a few meters in length
-body veriform
-complete gut (2 cavities)
The structure of the body wall of pseudocoelomates explained:
-muscles are longitudinal (no circular) beneath the hypodermis
-non-living cuticle secreted by the hypodermis
-composed of many layers of collagen
-useful for protection and containing high pressure of hydrostatic skeleton
-muscles contract and push against fluid which causes movement