Platyhelminthes (Flatworms)

Family: Platyhelminthes
This phylum is comprise of mainly planarians, tapeworms, and flukes. They are soft-bodied invertebrates that have a bilateral symmetry, meaning you can divide them into two identical parts. In addition, they can be either free-living, meaning they do not have to depend on a host, or parasitic. These three types may belong the to same family, but they all have different characteristics that separate them from each other.

Planarians
Planarians are flatworms that exist in the oceans, in fresh water, and in moist terrestrial habitats. A few are parasitic, while others are free-living. They have a flatten yet wide body structure, and can regenerate loss body parts when cut into small individual parts.

Tapeworms
Tapeworms are class of parasitic worms that invade and suck nutrients from animals' intestines. They are are flat in shape and are segmented (meaning each body part has the same identical pattern). These worms are often transferred when both humans and animals eat contaminated or infected food such as grazing in the pastures to eating under cooked poultry.

Flukes
Flukes have a flatten body shape just like the planarians & tapeworms. However, they are plump, looking much more like a blob of jelly. However, they still do have suckers, since they are parasitic invertebrates. Adult trematodes have two specialized suckers. One is an oral sucker that surrounds the mouth. The other is a ventral sucker in the middle of the body that helps trematodes hang on to their host.