The microstructures of several eutectic alloys were examined by scanning electron microscopy. Eutectic alloys of Ni-W, NiAl-Cr, NiAl-Cr (Mo) were directionally solidified and selectively etched to reveal the microstructure in three dimensions. A variety of rod and plate structures was observed that illustrates the rod-plate transition. In a nonfaceted rod eutectic, a fault structure consisting of branched rods and rod terminations was observed, while in a faceted alloy faults consisted of a web connecting two faceted rods. During solidification, the web structure splits into two faceted rods producing a plate to rod transition. The formation of a web between two rods causes the transition from rods to plate. In Ni-W, the rod structure transformed to plates in grains where the growth direction deviated from being parallel to the facet planes. It was concluded that alignment is a principle factor in the rod plate transition.