Phylum: Nematode or Nemata
Common name: roundworm
- Unsegmented worms
- Consists of pseudocoelomate and acoelomate worms
Around 30,000 species are known and described.
However, scientists believe that they could be counted in the millions,
but it is difficult to distinguish them because of their small size, similar anatomy, and their ability
to survive in a vast number of habitats.
- One of the most abundant multicellular animals alive today.
- Based on Biochemical Attributes
- Based on Morphological Detail
- Average length is 1mm-2mm long with no visible segmentation
- Both ends of nematode are tapered
- The outer multilayered covering is called a CUTICLE. This is collagen secreted by the epidermis. It is permeable for water and gas exchange but does not protect from dehydration. The CUTICLE is shed and resecreted 4 times during their development.
- Their bodies are filled with pseudocoel fluid which acts as a circulatory medium.