ammonoid


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Related to ammonoid: ammonite, Ammonoidea

ammonoid

(ăm′ə-noid′)
n.
An extinct cephalopod mollusk of the subclass Ammonoidea of the Devonian to Cretaceous Periods, having a straight or coiled chambered shell characterized by more or less intricate suture patterns where the septa between individual chambers join the outer shell wall.
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