Last modified on July 23rd, 2020 at 8:37 am

Details About Box Jellyfish Anatomy

Box jellyfish (class Cubozoa) are cnidarian invertebrates recognized by their cube-shaped medusae. A few types of box jellyfish deliver intense venom: Chironex fleckeri, Carukia barnesi and Malo kingi. Stings from these and different varieties in the class are results in excruciating pain and can be deadly to people. They are normally found near Australia, and seasonally near Hawaii.

Box Jellyfish Nomenclature

“Box jellyfish” and “sea wasp” are basic names for the very venomous Chironex fleckeri. However, these terms are vague, as “sea wasp” and “marine stinger” are now and again used to allude to other jellyfish.


The medusa type of a box jellyfish has a squarish, box-like bell. From each of the four lower corners of hangs a short pedalium or stalk which bears one or more long, thin, empty tentacles.

The edge of the bell is collapsed inwards to shape a shelf known as a velarium, which limits the bells aperture and makes a powerful stream when the bell pulsates. Thus, they can move more quickly than other jellyfish; reaching speeds of up to six meters/second.

In the center  of the underside of the bell is a versatile limb called the manubrium, which looks like an elephant’s trunk. At its tip is the mouth. The inside of the bell is known as the gastrovascular cavity. It is separated by four equidistant septa into a main stomach and four gastric pockets.

The eight gonads are situated in sets on either side of the four septa. The edges of the septa bear sections of small gastric fibers which house nematocysts and digestive organs and stifle prey. Every septum is stretched out into a septal tunnel that opens onto the oral surface and encourages the stream of liquid into and out of the animal.

The Box Jellyfish’s Sensory System

The box jellyfish’s sensory system is more evolved than that of numerous other jellyfish. They have a nerve ring around the base of the bell that facilitates their movements.

Though some other jellyfish have basic pigment cup ocelli, box jellyfish are remarkable in their possession of well-developed eyes, containing retinas, corneas and focal points. Their eyes are set in bunches called rhopalia, situated in pockets most of the way up the external, level surfaces of the bell.

Each eye contains two rhopalial ocelli with focal points; one positioned upwards and the other downward and inwards towards the manubrium. This enables the creature to see more specific objects, instead of just recognizing light and dark. Box jellyfish additionally have twenty ocelli (basic eyes) that don’t allow them to see pictures. However they do allow the animal to recognize light and dark.

They show complex, most likely visually guided practices like predator evasion and quick directional swimming. Research demonstrates that due to the quantity of rhopalial nerve cells and their general organization, visual processing and reconciliation at least partly happen inside the rhopalia of box jellyfish.

The complex sensory system underpins a moderately progressed framework. When compared to other jellyfish, and box jellyfish have been portrayed as having a dynamic, fish-like behavior.

A few species have tentacles that can reach up to 3 m (9.8 ft) long. Box jellyfish can weigh up to 2 kg (4.4 lb).

Julie Adams

I have been a nature enthusiast since I was a small girl. My background is in online marketing and website development. It only makes sense to merge my love for nature with my skills in online marketing to help spread awareness, and appreciation for Our Beautiful Planet.