Vernon, California, is a gritty industrial city about five miles southeast of downtown Los Angeles, its humble skyline dominated by wholesale food distributors, meat-processing plants, and assorted warehouses. One of those sprawling buildings is the unlikely home of the Natural History Museum of Los Angeles County Marine Mammal Laboratory-- 16,000 square feet of floor space on an obscure street, with no sign to mark the entrance to the small parking lot. On most days it would probably be very difficult to find. On this day, however, two frozen dolphin carcasses, sitting outside on the pavement near a loading dock, give the lab away.