The Physalia physalis, typically called the Portuguese Man O' War, is usually described as a jellyfish, but this is not true. It's actually a siphonophore. A siphonophore is an animal that is made up of many organisms working together with individual polyps specified for such things as moving, feeding, asexual reproduction, and digestion. The Portoguese Man O' War is common around the tropics but can be found throught most of the Atlantic Ocean, Pacific Ocean, and Indian Ocean. It is a common food source for sea turtles.
Source: 4Neus---License
The Man O' War is made up of four polyps. The upper most polyp is what is used as a float. This polyp is where the name "Man O' War" comes from since it resembles a Portuguese Man of War ship from the 18th century when the polyp is full of Argon gas.
The second most important polyp is the one that consist of tentacles and stinging cells, nematocysts. This polyp is where the Man O' War catches all of its prey and essentially lets it feed. These tentacles can grow up to 165 feet long (~51 meters) but usually stay around 50 feet ( ~15 meters).
These tentacles also act as a defense mechanism since they are able to sting without feeding after. A sting can range from extremely painful to life threatening as some cases have been fatal.
As mentioned previously, there is a polyp specifically for reproduction.
According to marine biologist Helen Scales,
"They produce sperm and eggs. In fact, you get female and male Portuguese man-o-war, even though they're called "Men"!
The sperm will fertilise eggs in the water column to produce larvae, which grow into bigger Portuguese man-o-wars.
The way that they grow from those individual cells is by asexual division of those cells and they produce all those individual three types of animals that live in this one colony and drift around the oceans, stinging things and eating things as they go."
I'll leave this one to her explanation since it is a lot better than what I would be able to communicate.
The last polyp is for digestion. This is pretty simple: the prey is brought to the digestive polyp, digestive enzymes are released to breakdown proteins, carbahydrates, and fats, the enzymes liquify the organism, and then the leftover, non-liquid, remains are expelled.
http://eol.org/pages/1005764/details
https://oceanservice.noaa.gov/facts/portuguese-man-o-war.html
http://www.untamedscience.com/biodiversity/portuguese-man-war/
http://oceana.org/marine-life/corals-and-other-invertebrates/portuguese-man-o-war
