- These animals are bilaterally symmetrical, triploblastic.
- They show a new feature of body design, namely a notochord , at least at some stages during their lives.
- The notochord is a long rod-like support structure (chord=string) that runs along the back of the animal separating the nervous tissue from the gut.
- It provides a place for muscles to attach for ease of movement.
- Protochordates may not have a proper notochord present at all stages in their lives or for the entire length of the animal.
- Protochordates are marine animals.
For Example: Balanoglossus, Herdmania and Amphioxus
