If ""The Fisherman and His Wife"" must be illustrated, let it be by Margot Zemach--who has the comic-cataclysmic range, the vigor, the intelligence for the task. We first see the fisherman and his wife scrunched into their pigsty, sleeping, on the half-title page--and, without a word, know them for what they are: his head is gently inclined, hers stubbornly uptilted. Overleaf, as they yawn and stretch, the outline of a large house is visible on the heights beyond. And on the first page, when the fisherman finds the flounder, the couple's fate is fore-shadowed in the sepulchral visage of that enchanted being. As the fisherman's wife asks for more and MORE and MORE, the illustrations rise to heights of comic grandeur; as the fisherman returns time and again to the flounder, the sea darkens and roils, the sky darkens, flames, explodes. . . until finally alt her folly is swept away in the maelstrom; and, on the last page, we see the two patching up the pigsty. She has asked, in Randall Jarrell's well-chosen words, ""to be like the good Lord."" His is a less patterned telling than, say, Wanda Gag's--richer in language, fuller in incident. A great drama is enclosed in these few pages--though one misses some of the deeper soundings that come, perhaps, from attending only to the tale.