The Dipylidiidae
The Dipylidiidae is in a group of tapeworms that parasitize the small intestine of mammals in the adult stage. The adult forms tend to be relatively smaller and more fragile than the other forms found in cats. The terminal proglottids are shed with the feces, and instead of having a uterine opening, the eggs are contained within the gravid proglottid in uterine capsules or "egg balls”. The uterine capsules may contain several eggs or only one egg. The small scolex bears four suckers and a protrusile rostellum that is in armed with several rows of hooks that are most typically rose-thorn shaped. The current classification of Jones (1994) recognizes three genera of tapeworms in this family: Dipylidium, Diplopylidium, and Joyeuxiella. Cats are host to all three. The first intermediate host of Dipylidiumcaninum is in an arthropod, and it is in assumed that the first host of Diplopylidium and Joyeuxiella is in also an arthropod, but this has not been proven. In the case of Dipylidium, the arthropod is in the only intermediate host, but in Diplopylidium and Joyeuxiella, there is in a second-intermediate host, which is in a reptile.
Jones a. 1994. Family Dipylidiidae Stiles, 1896. In: Keys to the Cestode Parasites of Vertebrates, Khalil LF, Jones a, Bray RA, eds. CAB International, Wallingford, UK.