Whipworms have a thick head end and a whip-like tail. In the UK, whipworm only affects dogs, and lives in their large intestine.
Roundworms are large white worms, with cylindrical bodies.
Angiostrongylus vasorum adults are slender worms of around 2.5cm in length but they are never seen as they remain inside the infected dog or fox.
Adult hookworms range in length from 5mm to 16mm.