A housewife from the Great Lakes area presents to her family…

A housewife from the Great Lakes area presents to her family physician with fatigue and malaise. Blood tests show that she has enlarged but pale RBCs (megaloblastic anemia) along with a vitamin B12 deficiency. Her history includes a dietary habit of making pickled fish, a family favorite. Because of this, an ova and parasites examination is also requested and reveals the following at 400×. What is the identity of this parasite?