Comments

  1. says

    The nautilus has always been one of my favorites. :-)

    I found a nautilus shell once on a scuba dive.

    Cuttlefish also hold a special place in my dark, evil, heart.

    Cheers.

  2. CaseyL says

    Holy guacamole. What an amazing critter.

    I had no idea nautilii had such… odd decolletages. I thought they were basically squids-in-shells, and what came out of the shell were the eyes and tentacles. Now it seems they have a flap or sheath or something for each tentacle (as the linked side-view photo seems to indicate)?

    Is this one only half-deployed?

    Oh, and what’s that yellowish, rather phallic-looking thungummie right above the all-purpose opening, there?

  3. Colugo says

    I always had a soft spot for spiral-shelled cephalopods – nautiluses, ammonites, and argonauts.

  4. Chinchillazilla says

    If I had a nautilus, I would name him Captain Nemo.

    Because I can, that’s why.

    Hush.

  5. Anton Mates says

    It’s a protostome. It uses that opening right there in front for everything.

    No, protosomes have two main holes just like us; we merely switched their roles.

    The cephalopod anus is tucked away in the mantle cavity, but it’s there.

  6. David Marjanović says

    No, protosomes have two main holes just like us; we merely switched their roles.

    There is no switching. In protostomes the blastopore usually closes in the middle and forms the whole digestive tract that way; in deuterostomes it becomes the anus only, and the mouth is new. In vertebrates, incidentally, the caudal neuropore closes over the blastopore, and the anus forms later, independently.

  7. David Marjanović says

    No, protosomes have two main holes just like us; we merely switched their roles.

    There is no switching. In protostomes the blastopore usually closes in the middle and forms the whole digestive tract that way; in deuterostomes it becomes the anus only, and the mouth is new. In vertebrates, incidentally, the caudal neuropore closes over the blastopore, and the anus forms later, independently.