Portuguese Man-of-War (Physalia
Photo by Tori Lindo
Negative photo image to show tentacles below water.
Man of War scientific
Species: Physalia physalis
What the heck is a siphonophore?
Biologist and scientists like to have a catalogue
or a reference database of scientific and common names of animal species of all life known as the Integrated Taxonomic
Information System. The outline or rank of this system is stated as: Kingdom, Phylum, Class, Order, Family, Genus
and Species.  
Is the man-of-war
All jellyfish are “jellies,” but not all jellies are jellyfish. Jellyfish or “true jellies” belong to the phylum
Cnidaria. Jellies are any animals that have gelatinous body forms and live in the water. 
The different morphologies (structure)
that represent jellyfish have several different cnidarian classes including the Scyphozoa (the true jellyfish class
wtih 200 species), Staurozoa (stalked jellyfish, 50 species), Cubozoa (box jellyfish, 20 species), and Hydrozoa
(man-of-war, 1000-1500 species). 
The Man-of-War on first observation
is different then a jelly based on the floating crest above the water as shown in the photos on the left. The Man-of-War
can also deflate the crest and submerged completely underwater. It also uses a propulsion system to move through
the water unlike the jelly which performs contracting and relaxing of muscles in the umbrella. The biological side
of the man-of-war is made up of a colony of organisms working together which is not present in the jellyfish.
In summary, we can say the man-of-war is related to the jellyfish, but belongs to a different class.