Hemichordata: Classification , Characteristics & Diagrams
Hemichordata
Hemichordata is a marine animal distributing in all over the world named by Delle Chiaje in 1829. The word Hemichordata is coming from the Greek word Hemi means half and Chordae means string. About 90 species of it have been described by scientists till now.Classification of Hemichordata -
- Kingdom - Animalia
- Phylum - Hemichordata
- class- Enteropneusta and pterobranchia
- Higher classification - Deuterostome
Commonly name - Acorn worms
Habitat - Hemichordata is a marine invertebrate living in the depth of solid substratum like under rocks, in the mud.
General Feature -
- Hemichordata has some features of the chordate family.
- They follow bilateral symmetry.
- The body is divided into three portions - collar, trunk, and proboscis lobe.
- Reproduction in Hemichordata is of sexual type.
- The glomerulus is present in the form of an excretory organ.
- They have an open circulatory system.
- Fertilization is external. They have sometimes indirect development through a swimming tornaria larva.
- The central nervous system is absent; all the nervous tissue is concentrated in the collar which is connected to the nervous system of the epidermis or outer covering.
- They have pharyngeal gill slits for respiration.
- Coelom is divided into three area : protocoel , mesocoel , metacoel .
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