A removable cassette for a peristaltic pump includes a cassette body and an occluder disposed at least partially in the cassette body and configured to be movable between an occluding position and a non-occluding position. The occluder includes an occluder body and an anti-ejection member integrally formed on the occluder body. The anti-ejection member is configured to substantially prevent the removal of the cassette from the peristaltic pump when the occluder is in the non-occluding position.