There are many which might have oval or close to oval shells, but one that comes to mind quickly is the cowry, some of which are nearly perfectly olive shaped (Class Gastropoda, Family Cypraeidae).
they live in the shells.
most have shells
They have shells.
Mollusks have soft body and hard shells but some don't even have shells.
clown fish
Yes, they are mollusks as well
crustations
Slugs,Octopus
Mollusks are soft bodied animals that can have no shells,1 shell or even 2 shells. Snails, clams, sea slugs, clams, scallops, oysters, octopuses, and squid, are some types of Mollusks.
Norman W. Lermond has written: 'Shells of Maine' -- subject(s): Mollusks 'Shells of Maine' -- subject(s): Mollusks
Conchology is the study of mollusk shells, therefore a conchologist is someone who studies mollusk shells. Some confusion can arise as malacology is the study of mollusks as whole organisms, while conchology only studies the shells themselves.
mollusks are slow-moving in the way that they are soft-bodied animals and protected by shells.