PETER COTTONTAIL'S SURPRISE by Bonnie Worth, illustrated by Greg Hildebrandt (Unicorn: $11.95, ages 2-8 and rabbit-tale aficionados of all ages). At Easter in 1952, kids were treated to a new holiday song with the words: "Here Comes Peter Cottontail hopping down the bunny trail . . . " If Peter Cottontail slipped into the national consciousness in the early '50s, he certainly missed mine. Now, I am happy to report, he has made a second official appearance for Easter 1985 in the form of a storybook character, the hero of his very own, uh, tale. (In his little blue jacket, Peter Cottontail looks a lot like a rabbit I was acquainted with as a child, Beatrix Potter's mischievous Peter Rabbit.) Bonnie Worth's plot here pales next to Greg Hildebrandt's illustrations, which--reminiscent of the work of Michael Hague and Eileen Atkinson--are rich in tone, detail and golden light. Worth's character Peter Cottontail may be hippity-hopping down the trail, but he comes across as a wimpy, timorous little guy afraid to face the meadow alone and no match for Beatrix Potter's devil-may-care Peter Rabbit. Still, he comes beautifully bound in a navy cloth cover, with 48 full-color, heavy-duty glossy pages, a delightful addition to any Easter basket.