MEXICO CITY (AP) — Activists and artists in Mexico held a mournful, dirge-like procession for the critically endangered vaquita porpoise Saturday, as the species' numbers fell below 30. With drums, chimes and a carved vaquita skull, hundreds of people made their way through a downtown Mexico City park. Organizers said the procession wasn't a funeral for the vaquita, but experts suggest that perhaps as few as 18 remain in the upper Gulf of California, also known as the Sea of Cortes.