Looks like a cross between a scorpion and a tick.
Tiny (less than 1/4"), spreading everywhere on old sea lettuce. Each has a tiny reddish orange top.
About 1/2". Was found on sea lettuce, which was pumping out bubbles of oxygen which stuck on the limpet's shell.
About 2" high, brown and white stripes.
Maybe "Parasol Feather Duster" (old names: Demonax medius or Sabella media).
Another one, darker (orange on one side, balck or dark brown on the other).
"Orange Finger Sponge," ID as per Lamb and Hanby p. 68.
Lacy, fine, nearly translucent light brown algae (or possibly seaweed) growing profusely on dock. Clumps 6-12" but hard to tell where one ends and he next one starts because it was so fragile.
"Spaghetti Sponge," ID as per Lamb and Hanby, p. 62.
About 1/2" long, saw several of them in various red/yellow/orange colors speeding along just below the surface of the water.
AKA Japan Mussel.
I'm no expert, but all of the Lake Merritt C. percas I've seen have 2 unique characteristics --
1) two tiny black 'eyespot' dots behind their rhinophores, and
2) faint white bands near the tips of their cerrata
Neither of these characteristics are mentioned in Beherens 'Eastern Pacific Nudibranchs,' p. 128, although his photo does seem to show the 'eyespots.' Has anyone noticed these markings anywhere else but Lake Merritt?