ganglia
Trematoda
Groups of nerve cells that control the nervous system are called nuclei in the central nervous system and ganglia in the peripheral nervous system. These clusters of nerve cells work together to regulate various functions such as movement, sensation, and organ functions.
Flatworms, Roundworms, Annelids, Mollusks, and Arthropods
Flatworms are divided into two groups, parasitic and nonparasitic. The parasitic types, which live off of other organisms, consist of Cestoda, Trematoda, and Monogenea flatworms.
Many flatworms can detect changes in the amount of light in their environment using groups of cells called photoreceptors. These cells are sensitive to light and help the flatworms navigate and respond to their surroundings based on light levels.
Acoelomate animals, like flatworms
Involuntary and voluntary actionssomatic nervous system and autonomic nervous system
No, ragworms are polychaetes under phylum Annelida (rounded worms). Platyhelminthes are the flat worm phylum.
Involuntary and voluntary actionssomatic nervous system and autonomic nervous system
there are: roundworms, flatworms, jellyfish, crustations, myrapods, arachnids, insects and im sory there are a couple more which i cant remember.
Soft bodied invertebrates classified into three groups based on body structure are flatworms, roundworms, and segmented worms. Flatworms have a flattened body, roundworms are cylindrical with a tapered ends, and segmented worms have distinct body segments.
If I remember correctly, there is of course the central nervous system and the peripheral nervous system, further divided into the sympathetic and the parasympathetic nervous systems.