cephalaspid การใช้

Ostracoderms existed in two major groups, the more primitive cephalaspids.
The shells of the Volvatellidae and Oxynoidae somewhat resemble those of the Cephalaspid bubble snails.
The cephalaspids were more advanced than the heterostracans in that they had lateral stabilizers for more control of their swimming.
Most biologists regard this taxon as extinct, but the name is sometimes used in the classification of lampreys, because lampreys were once thought to be related to cephalaspids.
At present, the oldest known " Undichna " were made by Cephalaspids, that only had presumptive motion scenarios, due to the mya, in an ancient riverbed environment.