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What are anemones?
Anemones belong to the phylum Cnidaria, which means stinging animals. Anemones have tentacles which paralyze their prey, and bring their prey towards their mouth. Their tentacles have nematocysts which shoot out toxins after their tentacles come in contact with certain stimuli. They are radially symmetrical which means you can cut them in half and they would be symmetrical. Sexual and asexual reproduction may occur in anemones. Anemones are all sessile, which means they cannot move, except for their tentacles. They have a mouth surrounded by tentacles, and a body which contains a gut. The gut is the gastrovascular cavity, which is used for internal digestion.

What are Anthopleura xanthogrammica?
Kingdom: Animalia
Phylum: Cnidaria
Class: Anthozoa
Order: Actiniaria
Family: Actiniidae
Genus: Anthopleura
Species: xanthogrammica

This anemone has captured a mussel, and its sticky tentacles are bringing it towards its mouth.

The anemone has brought the mussel to its mouth via the tentacles, by folding its tentacles and its squeezing its' body inward.

The mussel is now inside the anemones' gastrovascular cavity, and internal digestion is occurring. The tentacles have returned to their normal location.

Anthopleura xanthogrammica are a species of anemone, also known as the Giant Green nemone. They are found in the low intertidal to the sub-intertidal zone from Alaska to Panama. They are found in either sand or gravel filled pools on rocky shores. They have an emerald green oral disk which is broad and flat, and can reach up to fifteen centimeters in diameter. Their columns are either olive or brown. They have warts on the upper third section of their column. Tentacles shoot out threads which engage their prey. Evidence is present that suggests suction occurs during this process. They eat mussels, crabs, sea urchins, and small fish. The reason they are green is because they contain algae in their tissues. These algae are called zoochlorellae, and zooxanthellae. Although A. xanthogrammica are carnivorous, but there is evidence that the algae have organic compounds which provides this anemone with nutrition. Their mouth is also their anus. In the late spring and summer males release their sperm which stimulates the females to release their eggs, and fertilization occurs in the environment. They can also reproduce asexually by budding, binary fission, and pedal laceration. Their predators include some nudibranchs which eat their tentacles. Nudibranchs do this because the toxins in the anemones' tentacles gives them a bright color which scares off the nudibranchs predators.

What are Metridium senile?

Kingdom: Animalia
Phylum: Cnideria
Class: Anthozoa
Order: Actiniaria
Family: Metridiidae
Genus: Metridium
Species: senile

We are feeding M. senile zooplankton through a turkey baster.

The tentacles are bringing the zoopankton into the anemones' gastrovascular cavity.

The tentacles have brought the zooplankton into the gastrovascular cavity so internal digestion can begin.

These anemones are found in the intertidal zone, away from waves, on wood, shells, and rocks which are located in muddy bays. The difference between M. senile and other anemones is that they may have hundreds of tentacles, but their tentacles are very small. The number of tentacles they have increases as they grow. They can be more than twenty-five centimeters tall. White, tan, brownish-orange, or similar colors are the colors of the column. Their tentacles can be greyish or whitish. A white ring is sometimes located around their mouth. Their oral disks are well muscled. Small zooplankton, and small scraps of fish is what they feed on. Asexual reproduction occurs by fragmentation of the basal disk, or by pulling itself into two parts. This is known as laceration. Sexual reproduction occurs by releasing the sperm and eggs through their mouth into their environment. Their mouth is also their anus.

Questions and Answers about other Cnidarians

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