Gelatinous filter feeders, at times important phytoplankton grazers.

The spin a transparent mucilaginous "house", in which they live. Their body consists of a trunk and an elongated tail, which they beat to set up a current that draws water into the house and through a fine filter, on which phytoplankton is collected.

Larvacean, along with salps (tiny free-swimming organisms that has a transparent barrel-shaped body), belong to the invertebrate protochordate subphylum of the phylum Chordata (which is mostly made up of vertebrates).