As “The Rememberer” opens, the female narrator informs readers that her lover is “experiencing reverse evolution.” A sentence later it becomes clear that she does not mean this in a figurative sense; her lover, Ben, turned first into an ape, and now, a month later, he is a sea turtle.

After this startling introduction, Annie, the narrator, explains that she has determined Ben is “shedding a million years a day.” His office has called asking where he is, and Annie told them he was sick. She keeps Ben, the sea turtle, in a baking pan full of water; each day when she returns home, he has regressed into a more primitive form.

Annie describes the day he first began his backwards journey; Ben had been lamenting, in his sad way, that people think too much. “Our brains are...