What's the difference between heterocercal and heterocercy?

Heterocercal

Definition:

• (a.) Having the vertebral column evidently continued into the upper lobe of the tail, which is usually longer than the lower one, as in sharks.

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Heterocercy

Definition:

• (n.) Unequal development of the tail lobes of fishes; the possession of a heterocercal tail.

Example Sentences: