Never was counting more fun than with Wormell's boldly beautiful linoleum-block prints. The sequence goes from 1 (rhinoceros horn) to 20 (barnacle shells on a whale). Each image is reinforced by a facing page showing the Arabic numeral, the number written out and a brief description of the critter part being counted. As the numbers go up, the images tend to get more complex (16 catfish whiskers, 18 diamond markings on a rattlesnake), but even the simpler ones are ingenious, as in a chameleon's three colors blending into a tricolor scene. After 20, the book takes us back to 1 with a lone humpback whale an invitation to start over, which little arithmeticians will want to do again and again.