Pravitoceras (Prehistoric World by CollectA)4.8 (18)
Most paleontology enthusiasts are familiar with ammonites, the predatory mollusks with muscular arms and calcium carbonate shells. Most ammonites’ shells were disc-shaped coils (planispiral) that contained chambers, some of which afforded buoyancy, and one of which housed the squishy parts of the animal. One lineage of ammonites went a little wild with their shell coiling, producing some very strange shapes....