Sonninia sp. with passengers

This ammonite (18.5cm.) from the laeviuscula Zone, Bajocian, Middle Jurassic at Sherborne, Dorset, England has 2 snaily passengers on it. The first can be seen at the top and is probably an Euclocyclus sp. The other is an Orbonella sp. and is on the other side. See here: http://www.thefossilforum.com/index.php?/gallery/image/39987-orbonella-sp-deslongchamps-1849/