EXPEDITION: Being An Account in Words and Artwork of the 2358 A.D. Voyage to Darwin IV by Wayne Douglas Barlowe (Workman: $18.95). A popular paperback illustrator and the designer of the "Powerlords" toys, Barlowe combines the journal of a visit to a nearby planet with a lavish science-fiction bestiary. The main inspiration for "Expedition" seems to have been "After Man," biologist Dougal Dixon's zoology of imaginary future animals. What made Dixon's work so entertaining was the plausibility of the animals he described, which were designed on sound evolutionary and biomechanical principals. Barlowe's paintings and pencil sketches are handsome and slickly finished, and the fantastic denizens of Darwin IV he depicts resemble flanges from a Chinese bronze or Henry Moore sculptures. But these weird creatures lack the necessary aura of plausibility. Barlowe estimates the height of his Emperor Sea Strider--which looks like a cross between a dinosaur and a can opener--at 190 meters (about 600 feet), yet the monster is bipedal: Its enormous weight would have to be supported by a single foot-knee-hip structure during much of each stride, which is typically impractical and inefficient.