Definify.com

Webster 1913 Edition

Noun.

[

Pyro-

-some

body.]

(Zool.)

Any compound ascidian of the genus

Pyrosoma

. The pyrosomes form large hollow cylinders, sometimes two or three feet long, which swim at the surface of the sea and are very phosphorescent.

pyrosome ‎(plural pyrosomes or pyrosoma)

Any of several pelagic, colonial tunicates, of the genus Pyrosoma, found in tropical waters