This is a diagram of the cross section of a fish, showing the bilateral symmetry of the parts: dv, dorsoventral axis; vl, right-left axis. a.p., anterior appendage; b.c., body cavity; ch, notochord; d.f., dorsal fin; g, gut; h, heart; h.a., haemal arch; m, muscles; n.., neural arch; sp, spinal cord; v.c., vertebral column.

Fish

This is a diagram of the cross section of a fish, showing the bilateral symmetry of the parts: dv, dorsoventral…