Belemnites belong to the subclass Coleoidea, and they were numerous during the
Jurassic and Cretaceous periods. They are an extinct group of marine cephalopods,
similar to modern cuttlefish and squids.
The typical belemnite possesses a shell without a living chamber, and consists of three
clearly defined portions:
Figure 23: Morphology of a belemnite.
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Specimens with eight radiating sets of hooks have been found, testifying to the former presence of arms, and even fossilized ink sacs
have been located in place.
Figure 24: A rare impression of the tentacles of a belemnite.