Description of Nematobibothrioides histoidii (Noble, 1974) (Trematoda: Didymozoidae) and comparison with other genera.

Nematobibothrioides histoidii, inhabiting the body wall tissues of the sunfish, Mola mola, is characterized by its great length, reaching over 12 m, diverticulated excretory horns, large excretory tube, presence of 2 suckers, rudimentary pharynx, absence of gland cells around pharynx and ceca, oblong vitelline reservoir, and oval eggs, 17 by 15 mu. A description is given of the single species. Of 19 genera in the subfamily Nematobothriinae, 6 that possess the greatest similarity with Nematobibothrioides are compared. A brief discussion of didymozoid affinities is given.