THE MORPHOLOGY AND LIFE-HISTORY OF NEOPECHONA PYRIFORME (LINTON, 1900) N. GEN., N. COMB. (TREMATODA: LEPOCREADIIDAE)

¹ The American Museum of Natural History, Central Park West at 79th St., New York

The digenetic trematode described by Linton (1900) as Distoma pyriforme has been reported from many hosts and several species have been included in the accounts, with resultant confusion. It was included in the genus Lepocreadium Stossich, 1904 by Linton (1940), but it is not congeneric with L. album (Stossich, 1890), type of the genus. Its life-cycle has been elucidated; Anachis avara is the first intermediate host, where cercariae are produced in rediae. The cercariae are ophthalmotrichocercous, swim actively with the tail in advance. They penetrate but do not encyst in certain hydrozoan and scyphozoan medusae and in the ctenophore, Mnemiopsis leidyi. Developmental and adult stages resulted from ingestion of metaceracariae by the scup, Stenotomus chrysops. Eggs from worms were embryonated; miracidia emerged in 8 to 10 days, penetrated into A. avara, transformed into sporocysts, and produced rediae in 5-6 weeks. Worms recovered from S. chrysops are assigned to a new genus, Neopechona, and redescribed as N. pyriforme (Linton, 1900) new combination. The genus is included in the subfamily Lepocreadiinae Odhner, 1905.