Philomena Midge and Horace Abercrombie don't look as though they could be friends; the frilly-aproned hippo's cluttered old house is set in a profusion of flowers while the slimly elegant antelope's sleek abode features a spare Japanese garden, and their habits, too, are diverse. Still, Horace likes Philomena's cooking, and she likes his jokes; their rapport is the talk of the other animals until the two have a spat over a comic pratfall involving a bicycle, a pizza, and an umbrella. Smug friends are quick with advice (``You should ignore her from now on''), but a tie for the blue ribbon at a flower show brings them back together with exchanged compliments and apologies and companionable chuckles. The theme is familiar, but in Jacobs's excellent picture-book debut it's buoyed by entertaining details and a lively narrative. Gorbachev, a recent Ukrainian emigrÇ, provides delightful humanized animals enjoying the amenities of their world and reacting in various amusing ways to the protagonists' curious camaraderie. (Picture book. 4-8)