Triaenophorus adult

The scolex of Triaenophorus crassus is unusual for a pseudophyllidean tapeworm in that it possesses four tri-dentate hooks (clearly seen in the dorsal view of the scolex, top left) but it alsohas the bothria which are typical for pseudophyllideans (the lateral view in the lower left photo looks directly into one of the bothria).

The maturing strobila (right photo) illustrates that there is internal segmentation, but no clearly defined external margins to the proglottids. The genital pores alternate irregularly left to right, and the cirrus sac extends centrally to the midline of the body. Just beneath the cirrus sac is a small, bilobed ovary, and just below the ovary is a small Mehlis' gland. Above the cirrus is a small uterus, not yet containing any eggs. The numerous disks throughout the strobila are testes (larger) and vitellaria (smaller).