Masayuki NAKAJIMA ISu-mito Sea Paradise Aquarium, Nagahama, Numazu City, Sizuoka 410, Japan. Abstract
A lot of nematodes belonging to the family Pseudaliidae were obtained from the air sinus of the nasal cavity of a dolphin, Peponecephala electra, caught on the shoe of Futo, Shizuoka Prefecture in 1992. The body of the nematode was thick at the proximal portion, tapering toward distal end. There were 4 submedian papillae and 2 amphids on the head. six samll papilae were found surrounding posterior side of the mouth. Male worm had the bursa and spicles in the body, and the vulva was situated just anterior to anus. These findings indicated that the nematoda had the characteristics of the genus Stenurus, including egg system. Seven speces have been donfirmed in the genus Stenurus, including S. minor, S. ovatus, S. anditivus, S. globicephalae, S. pallasii, S. turuei and S. yamaguti. The specimens obtained from Peponocephla electra were compared with these nematode species in arrangeement and number of the head papillae, lobulation of the brusa of the male including the branching of dorsal ray, length of the spicules, the stracture of the uterus, vagina and vulva of the female, and the size of eggs. The comparative study showed that the morphological characterisctis of the nematode obtained from Peponocephala electra correspond entirely to those of Stenurus globicephalae Baylis and Dubney, 1925.