The ultrastructure of the mature spermatozoon of polyopithocotylean Pricea sp., a parasite of
Scomberomorus commerson was studied by transmission electron microscopy. The spermatozoon is
composed of two parallel axonemes, of the 9 +“1" pattern, one mitochondrion, a nucleus, cortical
microtubules. The main characteristics of this spermatozoon are the presence of one mitochondrion,
the two axonemes, which are of unequal length, and the cortical microtubules extend almost the entire
length of the spermatozoon.The present study indicated that spermatogenesis is connected to a
common cytophore. Spermiogenesis and the structure of the filiform sperm of Pricea sp conform to
the typical polyopisthocotylean pattern. Ultrastructural features are also discussed and compared to
other the monogeneans.