Status of Hemichordata
Hemichordata status Introduction Hemichordata was till recently treated as the sub phylum of the phylum Chordate but is now regarded to be the independent phylum of invertebrates very close to the phylum Echinodermata. The peculiar characteristics of the animals belonging to Hemichordata are as follows, Enterocoelus coelom Pharyngeal gill slits Buccal diverticulum (earlier considered as notochord) Vermiform body divisible into three regions – proboscis, collar, trunk The phylum hemichordate includes a small group of soft, primitive and marine chordates called as acron worms or tongue worms. Most familiar genus of this phylum is Balanoglossus which belongs to the class Enteropneusta. Other closely related genera are Saccoglossus, Glossobalanus etc. The class Enteropneusta was established by Gegenbaur in 1870. Since then due to the peculiar anatomical organisation and embryology, Hemichordata have...
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