any one of many extinct colonial marine creatures mainly associated with the purchases Dendroidea and Graptoloidea associated with the late Cambrian towards the very early Mississippian times, whose fossil keeps can be used to date the rocks associated with Silurian and Ordovician many years.
some of a small grouping of extinct aquatic colonial invertebrates, of this class Graptolithina, from Cambrian and Carboniferous times
One of numerous species of thin and delicate fossils, of this genus Graptolites and allied genera, based in the Silurian stones. They belong to an extinct team (Graptolithina) supposed to be hydroids.
one of several Graptolithidœ, Graptolithina, or Rhabdophora; a specimen or a species of Paleozoic cœlenterate organisms, generally allowed to be hydrozoans, resembling the living sertularians in having a horny polypary, plus obtaining the separate zoöids safeguarded by little horny glasses, all springing from a standard cœnosarc, but differing in that these people were maybe not fixed to your solid item, but had been permanently totally free.