Whelk
From my past experience of eating ocean snails, I think that they are not good to eat raw. Both raw turbo & raw trumpet shell (two types of ocean snail) were very tough - it went beyond being crunchy, even though they were served thinly sliced. It finally made my jaw muscles ache. Abalones are a kind of shellfish that has this sort of texture; they are often considered to be delicious.

There is a difference between ocean snails and bivalves, as far as their feeding habits are concerned. Ocean snails move actively, looking for seaweed, other shellfish, or sometimes small fish; bivalves, on the other hand, live in sand, stay in one place, and stretch their siphons out to suck in plankton from the sea. I guess the foot muscles of ocean snails, which we eat as sushi toppings, are well developed for that reason, and this makes their raw meat much too crunchy.

Being in the same category of ocean snail, the whelk has a texture different from other ocean snails when eaten raw. It is pleasantly tender, yet crunchy, and has a nice aroma of ocean. Well, I suppose from my description that it is obvious that I myself prefer whelk to any other shellfish tipping. But it is not only I who love whelks. They are a favorite shellfish topping among many Japanese people.* So at least, I’m not alone in my subjective preference!

*Some people say that whelk is a popular sushi topping among people of all ages when they go to conveyer belt sushi restaurants because of the tender, yet crunchy texture.

The species called “true whelk” is recognized as being the highest class (i.e., the most expensive) type of whelk. They prefer cold sea water, and the products from Hokkaido Prefecture (the northernmost prefecture in Japan) are often praised. After being de-shelled & having some of their inedible parts removed, the whelks are cut vertically and sliced diagonally & horizontally. The foot of the true whelk is covered with a blurry black and white spotted pattern; inside, its feet are ivory/cream-colored. Therefore, the whelk on sushi rice might look like a sliced semicircle with a stylish fringe of black and white dots.