Originally posted by MSaxatilus
Actually, Sushi is broken down like this.....
Rolls - well obvious, little pieces of fish rolled up in a bed of rice.
Sushi - is a piece of fish placed on top of a bed of rice.
Not to be too picky, but...
"Rolls" as you call them are referred to as "Maki" as in Maki Sushi
"Sushi" as you call it is referred to as "Nigiri" as in Nigiri Sushi.
Here is a clip from a sushi text:
SASHIMI
Sashimi is fresh, raw, chilled, sliced, and elegantly arranged. Ideally, sashimi is best when fresh, but most fish freeze well and are served after thawing.
Sashimi may be garnished with raw vegetables, leaves of knot grass, parsley, lettuce, shredded daikon, and sometimes seaweed or cucumber. Sashimi is odorless and very delicate. When sliced thick it is served with soy sauce, when sliced thin served with ponzu, a citrus flavored sauce. Wasabi, red pepper, and green onions may be served to mix with sauces as well. The beauty of the sashimi is that it lacks both the fishy smell and taste that would be its undoing.
MAKI SUSHI
Maki sushi contains strips of fish or vegetables rolled in rice and wrapped in crisp, thin sheets of dried seaweed. There are many combinations that even the most timid can enjoy- smoked salmon, fresh crab, or shrimp. The adventurous can sample delicacies like octopus, raw clams, sea urchin, or salted fish roe.
NIGIRI SUSHI
Nigiri sushi is a slice of fish (cooked or uncooked) pressed by hand onto a pad of rice. Fish roe is also served as nigiri sushi in a style called gunkan, meaning "boat". Nigiri sushi contains a hint of horseradish and is meant to be dipped in soy sauce. They are always served in pairs.
So-called California Rolls (rolled without seaweed) is purported to be a only-in-California invention.