The eggs of Fasciolopsis buski and Fasciola hepatica are among the largest seen in human specimens, measuring 130-150 micrometers long by 60 to 90 micrometers wide. The eggs of these two flukes are indistinguishable from one another, and therefore clinical correlation is necessary for determining the infecting organism when eggs are found in stool. These eggs are unembryonated when passed and have a thin wall with a small operculum at one end. The other end may appear roughened but there is no abopercular knob.