Having 4 cats, worms are sometrhing I am quite familiar with. The most common worms for cats are round worms and Tape worms. Round worms are very visable they are long and white often looking like spaggetti noodles. Kittens are often born with them. They are easy to identify when your cat goes to the bathroom.You can get rid of them with a over the counter dewormer quite easily. Tape worm is easy to identify once you know what to look for.I have told numerous cat owners that their cat has worms and they didn't even know it! It is not very visable in the cats feces, but the worms tend to cling to the cats rear end. They look like little pieces of dry rice or sesame seeds. You may find them where ever your cat sleeps if you look closely. Generally the vet will give you 1 to 1 and a half pills I think they are called Dronsit they cost between 8 and 10 dollars a piece. usually one dose is enough. It is important that you make sure your cat is flea free or they will probably be right back, all it takes is one flea to transmit tape worm. Fleas carry tape worm larvae they transmit it to your cat and it grows into a long yucky worm in your cat. The little rice pieces that you see are actually just little segments of one long worm!! There are other less common and more serious worms such as heart worms that only your vet can diagnose. I hope your cats are now worm free and happy!!