Select the incorrect statement from the following.

Coelenterates (e.g., Hydra) lack a brain. They exhibit a primitive neural organization with a network of non-polarised neurons. Ladder-like neural system is characteristically found in Platyhelminthes (e.g., Planaria). Arthropods (e.g., Periplaneta) have segmentally arranged ganglia joined by longitudinal connectives. Humans have a complex nervous system with a well-developed brain.