Question

This is an image of comb jelly. What is the common name of it?

A) Sea walnut
B) Sea gooseberries
C) Venus’s girdle
D) Thimble comb jelly

Answer 1

Comb jelly belong to the phylum Ctenophore which is derived from the Greek word which means to carry comb. The combs are the group of cilia that is used for locomotion. The comb jellies are invertebrates and live in marine habitats. They are the largest animal to swim in using cilia. These organisms show bioluminescence.

Complete answer:
Comb jelly is the marine predator which prey on microscopic larvae, rotifers, crustaceans. The size ranges from few millimetres to around 5 feet. The comb jelly shown in the figure is called thimble comb jelly. These organisms have an egg-shaped body and have a pair of retractable tentacles which have tentilla and are covered with colloblasts. The colloblasts are the sticky cells that these organisms use to capture prey. The body of these organisms is a mass of jelly and has a bilayer outside and another in the internal cavity. The organisms which prey on ctenophores are large-mouthed beroids and combless platyctenids. These organisms have a nervous system, muscles and other sensory organs. They are commonly known as Thimble comb jelly.

- Sea walnut: They are spherical, oval and small but lack tentacles. The body is made up of folds that resemble a walnut.
- Sea gooseberries: It is a spherical or oval-shaped organism that has long tentacles to catch prey that can be retracted.
- Venus’s girdle: It is the comb jelly that looks like a ribbon. They can be a metre long as well.

Thus, the correct answer is option ‘D’.

Note: This organism is colourless and transparent that live near the surface of the water. The ones that live deeper in the water have pigments and also show characteristic bioluminescence emitting blue and green colour which is only visible in dark. Some reflect the light through their comb and create the rainbow effect.