Dipylidium caninum is a tapeworm; what is the general class to which it belongs?

• A. Cestodes
• B. Nematodes
• C. Acanthocephalids
• D. Ciliates

Answer: (A)

Tapeworms, such as Dipylidium caninum, are classified as cestodes. Cestodes are flat, segmented parasites that attach to the intestinal lining with a scolex and reproduce via proglottids. They lack a true digestive system and absorb nutrients directly through their body wall. The life cycle often involves an intermediate host (in this case, fleas) before reaching the definitive host (dogs or cats).

This distinguishes them from other groups: nematodes are roundworms with a tubular digestive tract; acanthocephalids have a thorny proboscis and different body plan; ciliates are single-celled protozoa with cilia. So the correct classification for a tapeworm like Dipylidium caninum is cestodes.