Chondrophore

The chondrophores are small jellyfish-looking animal best known for their species known as By-the-wind-sailor (Velella velella) and the Blue Button (Porpita porpita).

Anatomy
Chondrophora contains a single family called porpitidae with two genera and six species. Chondrophores are related to jellyfish, but they are colonial animal made up of an orderly cooperative polyps. 

By-the-wind sailor's (velella velella), range in size up to 10 centimetres, and resemble the Portuguese man of war. However, they don't have a bladder, but a diagonal sail that could be work instead of bladder. 

Reproduction
When chondrophores are reproducing, a tiny medusa(0.3-2.5 millimeters or 0.01-0.09 inches) release and a medusae also grow new colonies. New colonies arised in the late proterozoic period(it is like 650~540 million years ago). Some have radiating tentacles that serve reproductive functions. 

Ecology
In the open ocean, the pelagic chondrophores are drifting and they face through the mercy of winds. we can see chondropores are in aggregation. A chondropores are eating a microplankaton that is chondropore's principle prey. They don't have stings, but they use skin to contact becuase of their irrigation. 

The colonial animals include vellela that catch their prey. The prey which vellela take is similar to a plankton and it is cnidoblasts on fine retractable tentacles and they live in the bottom of the ocean. 

The species of chondrophore, By-the-wind sailor, are living on the surface or warm seas world-wide. They eat creatures like a plankton. Sea slug(Fiona Pinnata), Sunfish(Mola Mola) and Violet sea snail(Janthina Janthina) eat the "By-the-wind sailors." 

Another species of chondrophore is Blue Button that belong to porpita. Their size is about 1centimeter across. Porpita has blue disc which acts to float and they have tentacles, but they don't sting human. They also live without sail. This could be found in Australia, Indo-pacific, and Atlantic waters. 

Genera
Chondrophora has two Genera which are porpita and vellela. The difference between porpita and vellela is that they are transparent. One of transparent is membranous sail-shaped floats which are filled with gas. The porpita and the vellela have dark blue mantles and tentacles that are called "turquoise". Vellela are 7.6centimeters(3inches) and porpita are 3.8centimeters(1.5inches). Both of them are especially large. 

Vellela are very small feature and are blue. They use a small stiff sail to catch the wind, and also push them upon the sea. Vellela also can come up on beaches.