Hemichordata
• Hemichordata was earlier considered as a sub phylum under phylum chordata
• Now it is placed as a separate phylum under no chordata
• Stomochord- Rudimentary structure in the collar region
• It is similar to notochord
• Small group of worm like marine animals
• Level of orgnisation- Organ system
• Symmetry- Bilateral
• Germ layer- Triploblastic
• Coleom- Colematic
• The body is cylindercal and composed of first 1.anterior proboscis
2.collar
, • Circulatory system- Open type
• Respiration- Through gills
• Excretory organ- Proboscis gland
• Sexes are separate
• Fertilisation- External
• Development- Indirect
• Example, Balanoglossus and saccoglauses
• # CHORDATA
• Fundamentally characterised by the presence of a notochord
• Odorsal hollow nerve cord and paired pharyngeal gill slits
• Symmetry- Bilaterally
• Germ layer- Triploblastic
• Hemichordata was earlier considered as a sub phylum under phylum chordata
• Now it is placed as a separate phylum under no chordata
• Stomochord- Rudimentary structure in the collar region
• It is similar to notochord
• Small group of worm like marine animals
• Level of orgnisation- Organ system
• Symmetry- Bilateral
• Germ layer- Triploblastic
• Coleom- Colematic
• The body is cylindercal and composed of first 1.anterior proboscis
2.collar
, • Circulatory system- Open type
• Respiration- Through gills
• Excretory organ- Proboscis gland
• Sexes are separate
• Fertilisation- External
• Development- Indirect
• Example, Balanoglossus and saccoglauses
• # CHORDATA
• Fundamentally characterised by the presence of a notochord
• Odorsal hollow nerve cord and paired pharyngeal gill slits
• Symmetry- Bilaterally
• Germ layer- Triploblastic