This photo shows a scolex, immature proglottid, mature proglottid and gravid proglottid . The scolex has four suckers for attachment to the host, but does not possess hooks. In the immature and mature proglottids the genital pores are unilateral, all emerging on the right side of the proglottid. The cirrus pouch is the brown tube that connects to the genital pore and travels medially. The three large, purple circular structures are testes; one is poral and two are aporal in location. To the left of the poral testis in the immature proglottid are the rudiments of the female genital system, which is seen to be developed in the mature proglottid. Most cestodes exhibit this protandry.
In the mature proglottid is a large, brown mass just above the poral testis. It is the external seminal vesicle. Above it is a purple, lobed structure, the ovary. Posterior to the ovary is a small, dark purple mass, the vitellarium. Cyclophyllidean cestodes such as this possess a compact vitellarium, in contrast to the follicular vitellaria possessed by other major cestode taxa.
The gravid proglottid is filled with eggs. About 500-1000 eggs are produced per proglottid, and each adult worm may shed a few dozen proglottids each day for the life of its definitive host.