What adaptations do leeches have in connection with a parasitic lifestyle?

It is believed that leeches lead not a parasitic, but a semi-parasitic lifestyle.
To such an existence, they have acquired some properties that help them in an effective existence.
The body of the leeches is shortened and flattened to hold it on the surface of the host’s body. In the digestive system, leeches have special protrusions that increase their capacity, allowing them to receive more blood from the host’s body.
The leeches have a special secret – hirudin, which prevents blood from clotting. Suckers act as attachment organs in leeches. And like most of the parasites of these animals, hermaphroditism is characteristic.