Chorda

... temperature, and pain sensitivity in the tongue, as well as taste. The gustatory fibres of the anterior tongue leave the lingual nerve to form the chorda...

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for example during neurulation the ectoderm differentiates into neural tissue by inductive compunds secreted by the chorda dorsalis (notochord).

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Hello I think cyclostomata own rudimental chondroid vertebrea or their basics which are located around the chorda. Also the other name for phylum vertebreta is usually craniata. That could diferentiate cyclostomata from the cephalochordata which i suppose have no cranium. (though ...

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