21. A hollow nerve cord is found in all chordates, including tunicates ( in the larval stage ). 22. The portion of the dorsal nerve cord in the collar region of Balanoglossus is the dorsal tubular nerve cord. 23. The portion of the dorsal nerve cord in the collar region of Balanoglossus is the dorsal tubular nerve cord . 24. The brains of arthropods and cephalopods arise from twin parallel nerve cords that extend through the body of the animal. 25. At least a pair of ventral nerve cords connect to the brain and run along the length of the body. 26. The main nerve cords of the central nervous system run through the length of the body from the pleural ganglia. 27. The nervous system is similar to that of other arthropods, including a ventral nerve cord with ganglia in each segment. 28. A layer of connective tissue called the neurolemma covers the brain, ganglia, major peripheral nerves and ventral nerve cords . 29. This behaviour is a reflex and does not require the CNS; it occurs even if the nerve cord is removed. 30. Because of the torsion of the nerve cords , one parietal ganglion is typically higher in the body than the other.
