Van Soest, 1979
Pyrosomatidae in which the cyathozooids produce 30-80 primary ascidiozooids in a whorled arrangement. Secondary ascidiozooids are unable to move once released from the stolon, remaining in the position established at budding. Growth of the test can push them farther away from the parent zooid. Colonial diaphragm absent. Colonial wall provided with low triangular "spines" or denticulations lying dorsal to the oral apertures of the zooids (Pyrostremma agassizi, Pyrostremma agassizi 1). Cloacal musculature on the branchial basket. Ventral and dorsal lateral muscular systems present.
Genus treated:
Genus Pyrostremma Garstang, 1929