contains many zooids which form a gelatinous tube, the walls of which range from 0.2 - 2.0 cm.

The zooids that make up a pyrosome are typically only a few mm long. Colonies of these zooids, which are bound together by a tunic of shared tissue, form a tube-like, hollow structure that is typically between 1 inch and 2 feet in length. However, giant pyrosomes can reach up to 60 feet in length, with a hollow opening up to 6 feet (2 meters) wide. There have been some instances in which deep sea scientists have swum inside of a giant pyrosome's