Identifying Meandrina: A Coelenterata Animal

The question asks for the generic name *Meandrina* to be matched with its common name among the provided options. The description points to a Coelenterata animal with soft tube-shaped bodies that live together in large groups. Let's break down the options based on this information.

Understanding Coelenterata (Cnidaria)

Coelenterata is an older term that primarily refers to the phylum Cnidaria. Cnidarians are aquatic animals characterized by radial symmetry, a sac-like body structure with a single opening (the mouth/anus), and the presence of stinging cells called cnidocytes. This phylum includes diverse organisms like jellyfish, sea anemones, hydra, and corals.

Analyzing the Options for Meandrina

We are looking for the common name for the genus *Meandrina*. Let's examine each option:

• Brain coral: Brain corals are hard corals (stony corals) that form large, rounded colonies with grooves and ridges that resemble a brain. The genus *Meandrina* is indeed a genus of brain coral. These corals fit the description of living in large groups and forming substantial structures on coral reefs. While the living tissue covering the stony skeleton is soft and polyp-based (tube-shaped polyps), the overall structure is hard due to the calcium carbonate skeleton they secrete. The pattern of *Meandrina* strongly resembles the convolutions of a brain.
• Sea anemone: Sea anemones are typically solitary polyps, although some species live in aggregations. They do not form the large, fused colonies characteristic of reef-building corals like brain corals.
• Sea-fan: Sea-fans are a type of soft coral (Gorgonians). They have a branched, fan-like or bushy structure supported by a flexible skeleton. While colonial, their body shape and overall structure are distinct from brain corals.
• Medusa: Medusa is the free-swimming stage of the life cycle of many cnidarians, commonly known as jellyfish. They have a bell or umbrella shape and are pelagic, not sessile organisms that live attached in large groups forming structures like corals.

Based on the biological classification and common names, *Meandrina* is specifically known as a type of brain coral. Its appearance and colonial nature align with the description provided in the question.

Conclusion on Meandrina and Brain Coral

The genus *Meandrina* belongs to the family Meandrinidae and is classified under stony corals (Scleractinia), which are notorious for building large coral reef structures. The common name that corresponds to *Meandrina* is Brain coral, reflecting the characteristic appearance of the colonies.

Therefore, the Coelenterata animal *Meandrina* is commonly known as Brain coral.

Revision Table: Meandrina and Coelenterata Facts

Additional Information: Types of Cnidarians and Corals

The phylum Cnidaria is diverse, including several classes. The animals mentioned in the options belong to different groups within Cnidaria:

• Anthozoa: This class includes sea anemones and corals (both hard and soft corals). They exist only in the polyp stage.
  • Stony corals (Scleractinia): These are the primary reef builders. They secrete hard calcium carbonate skeletons. Brain corals (*Meandrina*, *Diploria*, etc.) are stony corals.
  • Soft corals (Alcyonacea): These corals have flexible skeletons made of protein and spicules. Sea-fans are soft corals.
• Scyphozoa: This class includes true jellyfish. They spend most of their life cycle in the medusa stage.
• Hydrozoa: This class includes hydroids, some jellyfish, and Portuguese man-of-war. They can have both polyp and medusa stages, or predominantly one stage.

The question focuses on a specific genus, *Meandrina*, which is a type of stony coral falling under the Anthozoa class, commonly recognized by its Brain coral appearance.