Question

Feeding zooids of Physalia are called
A. Gastrozooids
B. Dactylozooids
C. Gonodendra
D. Gonopalpons

Answer 1

Hint: Physalia is a marine hydrozoan belonging to the phylum cnidaria. It is mostly found in the Atlantic, Indian and pacific oceans. It is having a zooid which is an organic body helpful in the spontaneous movement and for the existence of the organism independently as a parent organism.

Complete Answer:
Physalia is a marine hydrozoa of phylum cnidaria (coelenterata). They are diploblastic and have tissue level of organization. They have a single gastro vascular opening i.e. known as hypostome. Digestion is extracellular and intracellular. In Physalia, there are four different colonies that are present in polyp. These are:
- Pneumatophore: float
- Dactylozooids: tentacles
- Gastrozooids: feeding zooids
- Gonozooids: zooids that produce the gametes.

The correct option is A i.e. Gastrozooids.

Additional information: It has no means of propulsion therefore it moves passively driven with the winds, currents and tides.
- It is a sting filled with strong venom having neurotoxic, cytotoxic and even cardio toxic effects to humans.
- The name cnidaria is derived from the word cnidoblast or cnidocytes( which contain the stinging capsules or nematocysts) present on the tentacles and the body. Cnidoblasts are used for anchorage, defense and for the capture of prey.

Note: In Australia, South Africa and New Zealand they are also called Blue Bottles.
- These are also called as Portuguese man o’ war or man–of-war because of the resemblance with the 18th century sailing warship at full sail.
- These are sometimes referred to as floating terror because of their poisonous sting that causes severe pain.
- Obelia exhibit both body forms i.e. polyp and medusa due to the metagenesis (alternation of generation).