- It is a small group of animals, which include about 90 species.
- They are soft-bodied animals, which usually live in shallow “U” shaped burrows in the sandy or muddy sea bottom.
- They are cylindrical or vase shaped animals, bilaterally symmetrical and lack any segmentation.
- They may be solitary or colonial and usually range between a few millimeter and 250 cm in length.
- Sexes are separate in hemichordates.
- Circulatory system is open and coelom is divided into three chambers.
- A dorsal and a ventral nerve cord are present.