Billy Sundstrom, age 10, of Coventry, R.I., for his question:

WHAT IS A PORTUGUESE MAN OF WAR?

A Portuguese man of war is a giant jellyfish that floats on the surface of the ocean. You'll be able to find him in the Gulf Stream and other tropical waters.The creature is actually not a single animal, but a group of animals attached to a hollow float that looks very much like a bladder. A full grown float is about eight inches long and is filled with gas which allows it to float. Stringlike filaments called tentacles hang from the float and are often 100 feet long.

A Portuguese man of war's long tentacles act much as arms do since they grab food. They contain a poison that seems to paralyze fish. Humans must take care since swimmers touching the tentacles can suffer painful welts or even shocks and prostration that could be fatal.