 Often the two species can be confused, as "M. gracilis" looks very similar to a juvenile Dungeness crab.They can readily be distinguished from each other, though "M. gracilis" has a notch behind the widest point of its carapace that "M. magister" lacks, and the top joint of its pincers are not serrated like those of "M. magister".More obscure ways to tell are by the appearance of hair on the posterior three legs of "M. magister" where "M. gracilis" is almost always hairless.