Kids adore dinosaurs, but the marine reptiles that were their aquatic kin don't inspire the same passion. The new 3-D Imax feature "Sea Rex" sets out to correct that situation, but only partially succeeds. The French-produced primer on prehistoric ocean life suffers from rickety computer animation and a pedantic tone. The littlest sprouts will no doubt be thrilled by the sight of long-necked Plesiosaurs gliding through the deep, but their older siblings may squirm and snicker.

The 40-minute film opens on a parochial note, with a group of awestruck 18th-century French naturalists examining the fossil of a fish unlike any they have encountered. The discovery inspires young Georges Cuvier's eureka moment: Life began eons before us! The costume drama leaches into the 21st century as Cuvier's ghost (Richard Rider) approaches Julie (Chloe Hollings), a young woman in deep contemplation at an aquarium. After a formal "Pardon me for intruding on your thoughts," he offers a guided tour through vertebrate paleontology.

The exposition is awkward, and Rider and Hollings are stiff, as are some of the computer-graphic representations of early marine life. Still, the representations of geological epochs through color-coded time lines is effective in illustrating how recently we humans arrived on the scene.

Now and again the film brings in living experts to follow through on Cuvier's early work. Their presentations range from the straightforward to the outrageously hammy. One living scientist is represented onscreen by his walking, talking skeleton. It's a peculiar effect, but certainly novel.