For what it's worth, i'll share this:
our beach is a small cove, with both ends formed by rocky outcroppings which extend 60 yards or so into the ocean, forming incredible caves below the surface, which is maybe 30 or 40 feet deep at the end of the rocks. as you might imagine, this makes for absolutely *stellar* year-round snorkelling and diving (though the water gets too cold by mid-December for most of us, and doesn't warm up again til April or May. today it's only 58 - brrr~rrrr), as the sea-life is both varied and plentiful. you're guaranteed to see several bright-orange Garabaldi, which is a protected fish here in California, as you swim through schools of thousands of tiny fish which somehow you can never seem to touch, though at times it's as if you're parting a solid wall of them. there are often leopard sharks, which are stunning in their beauty and gentle unless cornered, as well as sandsharks, rays, halibut and other fish of every shape and size, so spearfishing is immensely popular among the residents. in addition to magnificent tidepools which boast crabs, anemones and urchins (which are edible but not particularly appetizing), the rocks near the surface provide homes to starfish, sea cucumbers (grossout) and (i'm getting slowly to my point here....) if you look carefully you're sure to find an octopus or two. these are small creatures (fist-sized discounting their tentacles), not the huge ones you see at disneyland's submarine ride.
okay, so here's my point, if anyone's bothered to read this far: since it's obligatory to report on what you saw as you climb back out onto the beach, i've seen folks (myself included) tackle the octopus/octopi/octipode conundrum quite often, and almost without exception we simply treat it as a collective noun; ie "I saw three leopard sharks, a halibut, and a couple of octopus". i guess it's probably poor grammar, but it would sound extremely stilted and pretentious if someone were to utter either "octopi" or "octopode" in anything other than an attempt at humor.
~b
