Happy as a Clam

Happy as a clam is a colloquial expression – a simile to describe a happy person. If a person is said to be ‘as happy as a clam at high water’ it means that they are content and satisfied. 

What is the origin of this expression? The website The Phrase Finder believes that it may have originated in America in 1833 in the book The Harpe’s Head – A Legend of Kentucky – “It never occurred to him to be discontented … He was as happy as a clam.” General Robert E Lee used the phrase too in the 1830s.

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What are the similarities and differences between the Giant Clam and the Maxima Clam?

What are the similarities and differences between the Giant Clam (Tridacna squamosa) and the Maxima Clam (Tridacna maxima)?

The Giant Clam and the Maxima Clam are both marine (saltwater), bivalve molluscs in the Cardiidae family. Bivalve means two valves (or two shells). They both prefer to live on the bottom of the ocean in shallow coral reefs.

The Giant Clam and the Maxima Clam both have a thick, ridged calcium carbonate shell, called a mantle. Their shells, which can open and close, have two equal-sized calcareous valves connected with a flexible adductor muscle. 

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Maxima Clam

The Maxima Clam (Tridacna maxima) is a marine (saltwater) bivalve mollusc in the Cardiidae family. It is also called the Small Giant Clam. It is related to the Cockle. 

The Maxima Clam has a thick shell called a mantle. Its shell is actually two equal-sized calcareous valves connected with a flexible adductor muscle. The shell can open and close. Bi-valve means two valves (or two shells). The mantle is bright-blue, green, or brown with distinctive furrows. It has a mouth, a heart, kidneys, a stomach, and a nervous system. 

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Common Octopus

The Common Octopus (Octopus vulgaris) is a marine (saltwater) invertebrate (soft-bodied) mollusc in the Octopodidae family. Octopod means eight limbs. It is a cephalopod, related to the squid, cuttlefish, and nautilus. 

The Common Octopus has a soft hollow body called a mantle. Its body can change shape and squeeze into small gaps. The mantle has gills (to breath), a brain, and a parrot-beaked mouth. Surrounding the mouth is eight limbs with suckers. It has two large eyes with excellent sight. It has three hearts.

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Soft-Shell Clam

The Soft-Shell Clam (Mya arenaria) is a marine (saltwater) bivalve mollusc in the Myidae family. It is also known as the Sand Gaper.

The Soft-Shell Clam has an elongated calcium carbonate shell that is thin and fragile (beach clams have thicker shells). The shell is called a mantle. It has two valves (two halves), joined together by a ligament hinge with two adductor muscles that enable it to open and close. It has paired siphons which helps it to breathe when it is under the mud. It has light-sensitive cells that can detect light and motion.

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Iberian Threeband Slug

The Iberian Threeband Slug (Ambigolimax valentianus) is a mollusc in the Limacidae family of air-breathing land slugs; a snail without a shell. It is a terrestrial (land) pulmonate (air-breathing) gastropod (one-footed) mollusc. It is also known as the Greenhouse Slug.

The Iberian Threeband Slug is usually pinkish with two faint narrow or broken bands down its body and mantle (shield on its back, behind its head) with a third midline band on the mantle. It has two pairs of retractable tentacles (feelers) on its head. One pair of tentacles is larger with eyespots on the tips. The lower, or smaller tentacles, provide the sense of smell.

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East African Keeled Land Slug

The East African Keeled Land Slug (Limacidae sp.) is an air-breathing terrestrial mollusc in the Gastropoda order and Limacoidea superfamily of keel-backed (ridgeback) slugs. It is a land snail without a shell. 

The East African Keeled Land Slug has a long white body with a mantle, a keeled (ridged) back and two pairs of retractable feelers on its head. The upper pair of feelers has eyespots at the tips. The lower pair of feelers contains sense organs. The mantle is a saddle-looking structure behind the head. On one side of the mantle is a respiratory opening, called a pneumostome. The body is also called the tail, which is behind the mantle. It has a ridge down the middle of the back of the tail. Its foot is the flat under-side of the slug. It secretes mucous that it travels on. 

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Abalone

The Abalone (Haliotis) is a sea snail. It is a marine (saltwater) gastropod mollusc. It is also known as the Sea Ear, Ear Shell, Muttonfish, and Ormer. It is a haliotid. 

The Abalone has a hard, convex, rounded or oval-shaped shell called an exoskeleton made out of nacre (mother of pearl). The shell can be domed or flat and it is usually greyish in colour. The inside of the shell is iridescent blue-green. It has a row of holes in its mantle, which enable it to breathe and expel water. About 4-10 holes are open. It has a rounded foot.

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CREATURE FEATURE: Giant Pacific Octopus

The Giant Pacific Octopus (Enteroctopus dofleini) is a large, marine invertebrate (soft-bodied) mollusc in the Octopoda order. Octopoda means eight limbs. It is a cephalopod, related to the squid, cuttlefish, and nautilus. 

The Octopus has a greyish, soft hollow body called a mantle. Its body can change shape and squeeze into small gaps. The mantle has gills (to breath), a brain, and a parrot-beaked mouth. Surrounding the mouth is eight limbs with suckers. It has two large eyes with excellent sight.

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What is the difference between a clam, a cockle, a mussel, and a scallop?

What is the difference between a clam, a cockle, a mussel, and a scallop?

The clam, cockle, mussel, scallop, and even the oyster, are all marine bivalve molluscs. Bivalve means two valves.

They all have a shell structure, called a mantle, with two valves (two halves) and a ligament hinge with two adductor muscles that enable them to open and close.

All bivalves have light-sensitive cells that can detect light and motion, even though most do not have eyes. Giant clams have simple eyes on the edge of the mantle. Scallops have more complex eyes on the edge of the mantle – they have 10-100 eyes that each have a lens, a two-layered retina, and a concave mirror.

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Scallop

The Scallop (Chlamys opercularis) is a small marine (saltwater) bivalve mollusc. It is also called a Clam, but it is not a true clam (a true clam does not live near the bottom of the ocean).

The Scallop has a white-creamy-yellowish-brown shell, called a mantle, with bilateral symmetry – its two valves are the same – connected by two hinge-type adductor muscles that enable it to open and close. Near the hinge are auricles. Auricles, like ears, are triangular protusions. The mantle has many ridges, called ribs, that fan out from the hinge. It has a foot which helps it to bury itself on the ocean floor.

The Scallop has 10–100 very small eyes along the edge of its mantle, which can detect light and motion. Each eye has a lens, a two-layered retina, and a concave mirror.

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Cockle

The Cockle (Cerastoderma edule) is a small marine (saltwater) bivalve mollusc. It is also called a Clam, but it is not a true clam (a true clam does not live near the bottom of the ocean).

The Cockle has a white-creamy-yellowish-brown oval-shaped shell, called a mantle, with bilateral symmetry – its two valves are the same – connected by two hinge-type adductor muscles that enable it to open and close. The mantle has many slight ridges, called ribs. It has a foot which helps it to bury itself in the ocean floor.

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Bluegreen Giant Clam

The Bluegreen Giant Clam (Tridacna derasa) is a marine (saltwater) reef bi-valve mollusc in the Cardiidae family. It is also called the Southern Giant Clam. It is related to the Cockle.

The Bluegreen Giant Clam is smoother than most clams, because it lacks ridging. It has a thick shell, called a mantle. Its shell is actually two equal-sized calcareous valves connected with a flexible adductor muscle. The shell can open and close. Bi-valve means two valves (or two shells). It has 6-7 rippled edges, called folds or flute. It does not have scutes (scales). The mantle has stripes or spots and is blue and green, with some white patches. It has a mouth, a heart, kidneys, a stomach, and a nervous system.

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Golden Apple Snail

The Golden Apple Snail (Pomacea canaliculata) is a freshwater South American snail. It is an aquatic gastropod mollusc (mollusk). It is also called the Channeled Apple Snail.

The Golden Apple Snail has a boneless foot with a brown globe-shaped shell, called a mantle. It has both external gills (like a fish) on the right-hand side of its body to enable it to breathe underwater, and an internal lung on the left-hand side of its body (like a frog) to enable it to breath on land. This means that the Golden Apple Snail lives in the water and on land – it is amphibious, like a frog or a toad. It also has an operculum, which is a little lid, that enables it to close the shell entrance to prevent it from drying out when it is buried in the mud during dry seasons.

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