Source : Webster's Revised Unabridged Dictionary (1913)

Homocercal \Ho`mo*cer"cal\, a. [Homo- + Gr. ? tail.] (Zo["o]l.)
   Having the tail nearly or quite symmetrical, the vertebral
   column terminating near its base; -- opposed to heterocercal.

Source : WordNet®

homocercal
     adj : possessing a symmetrical tail that extends beyond the end of
           the vertebral column (as in most bony fishes) [ant: {heterocercal}]