Thaliacea is a class of marine animals that belong to the phylum Chordata. They are small, gelatinous creatures that are primarily found in oceanic waters. Thaliaceans are known for their unique body structure, which includes a transparent, barrel-shaped body and a siphon for feeding and locomotion. They are often referred to as "salps" and "larvaceans," with salps being the more common type. These organisms play a significant role in marine ecosystems as they contribute to the ocean's food web. Thaliaceans filter plankton from the water, serving as a food source for larger animals like fish and whales. Their ability to rapidly reproduce and form large blooms can also influence nutrient cycling in the ocean.