This slide contains stained sections of the dog tapeworm Diplydium caninum taken from four different regions. The anterior most portion contains the scolex, a specialized attachment organ that often contains hooks and/or suckers.  The rest of the body is divided into a linear series of segments called proglottids, each of which contains a complete set of reproductive organs.  The youngest proglottids in the first part of the strobila (body) of the tapeworm are immature, while those in the middle are mature.  The oldest terminal proglottids are gravid, which means they are filled with eggs. Dogs and cats can become infected by eating adult fleas (the intermediate hosts) containing cysticercoid larvae.