Question

Features of protochordata

Answer 1

• Elastic, solid, ensheathed rod-like structure of vacuolated turgid cells callled notochord is present may be through out the life or only during early embryonic development mentioned above.
• Their central nervous System is dorsal,hollow and single which is different from non-chordata as their CNS is ventral,solid and double.
• Paired pharyngeal gill slits( pharynx is perforated by gill slits) is present which takes part in circulation of water for respiraton and in higher chordates , they occur only in embryonic stage.
• Ventral heart is present and gut lies ventral to nerve cord.
• Post-anal tail is present and if present then it's for balancing.
• They are bilaterally symmetrical, triploblastic, coelomate with organ system level of organisation.
• Urochordata and cephalochordata which are acraniates are considered as primitive and often referred to as protochordates or non-vertebrate chordates.