Zygobranchia
Zygobranchia , noun, plural
[New Latin, from Greek zygo`n a yoke + {not transcribed} a gill.]
(Zoology) A division of marine gastropods in which the gills are developed on both sides of the body and the renal organs are also paired. The abalone (Haliotis) and the keyhole limpet (Fissurella) are examples.