In addition, some specimens were hand-collected using plastic jars. Individuals of M. leidyi were hand-collected in the Bay of Piran in October 2005; similarly, Beroe ovata were hand-collected in autumn 2005. Individuals were maintained in a laboratory aquarium and photographed alive, while preservation in 2% neutralized formalin was not successful. Dimensions were assessed from photographs taken in the laboratory aquarium containing an object of known size. The Black Sea and the Mediterranean live individuals were put in Petri dishes with a small amount of seawater not completely covering the animal and then measured with a ruler. The same individuals were photographed and measured to make sure that measurements of individuals which were available only from photos are comparable with others.