Flotsam

Half a coconut

With a Red Sea Hare inside!

Exterior of the shell (I was careful not to tip the slug out)

Another slug

Weird seaweed(?)

Or possibly a tunicate

Some fellow beachcombers:

Godwit

Tern

Plover

Low tide

Bean clams
the green material is not seaweed, but a hydroid that anchors itself onto clams

Lots of bean clams

Chitons and limpets in a pool

Anemone

Royal Tern 

Crab in a crevice

Gradually crumbling cliff face

Spotted sandpiper

Rock tunnel exposed only when the tide is low

Seaweed garden

Hermits

Whimbrel

Sunset

Octopus fight!

A small California Two-Spot Octopus oozing its way around a tide pool:

Fishing

Then a rival appeared from under a rock:

Tentacle tug-a-war

Stretchy

Finally, one octopus turned a paler color, ejected ink, and shot off under another rock:

"I'm keeping an eye on you, land apes."

Shell & moss

Shattered spirals

Garden snail shells

Disc snail

Barely the size of my thumbnail.

Marine invertebrates

Flamboyant Cuttlefish:

Melibe, a sea slug:

Moon jellies: 

 

 

"A year at the shore"

Lovely illustrations of tidepool creatures from a book by 19th-century naturalist Philip Henry Gosse:

He also created some gorgeous illustrations of sea anemones.

Glass squid, illuminated

Scientists have discovered how two marine creatures are able to rapidly "switch" their colours - from transparent to reddish brown.
The species, an octopus and a squid, use their adaptable camouflage to cope with changing light conditions in the deep ocean...
The animals' skins contain light-sensitive cells called chromatophores, which contain pigments. When these cells detected the blue light of a bioluminescent predator, they immediately expanded, "dyeing" the animal a deep brown colour.
Dr Zylinski said the this dramatic colour change showed just how important camouflage was "in a habitat where there is nowhere to hide".
Neither transparency nor pigmentation is a complete solution to the hunting strategies used by predators in the deep ocean, she explained.
"By switching between these two forms, these cephalopods are able to optimise their camouflage in response to the optical conditions at that moment in time."

From BBC News.

The beautiful squid pictured above is named Leachia. It's one of many transparent sea creatures, along with jellies, crustaceans, and other cephalopods-- but as far as I know, none of those have the ability to change their opacity.

Ammolite

This colorful, rare gemstone comes from the fossil shells of prehistoric ammonites. Sometimes there are found whole shells composed of ammolite.