A NEWLY RECORDED HOST OF PAGUMOGONIMUS SKRJABINI: TRICULA HONGSHANENSIS SP. NOV.

A new species of the family Hydrobiidae from Dahongshan, Hubei Province is deseribed in this paper. Type specimens are deposited in Department of Parasitology, Faculty of Basic Sciences, Tongji Medical University.Tricula hongshanensis sp. nov. (Figs. 1—4)Diagnosis: Shell minute, conical, thin but opaque, Surface of shell smooth, chestnut brown, with very fine growth lines. Whorls 4(1/2)—5, each somewhat convex. Apex a little blunt. Suture well defined. Body whorl well inflated, occupying about 3/5 of shell length. Aperture ovate, peristome continuous. Outer lip thin, simple, with an acute angle(70—75°) at upper boredr. Inner lip slightly expanded, not attached but forming a rift from body whorl. Umbilicus rather small. Operculum ovate, yellowishbrown, thin and corneous, with radial growth lines. Operculum 0.91—1.02 by 0.68—0.72mm in size, capable of retracting into aperture. Radula band 0.74—0.81mm in length and 0.061—0.068mm in breadth, with radual formula:3—1—3/2—2; 2—1—3; 13—15; 19—22.Holotype: Shell 2.58mm long, 1.39mm wide. Aperture 1.15mm long, 0.69mm wide, collected on July 19, 1984.Paratype(10 specimens): Shell 2.26—2.66mm long, 1.29—1.52mm wide. Aperture 0.98—1.25mm long, 0.62—0.73mm wide.Localities: Suizhou and Zhongqiang of Hubei Province.Parasite: Cercaria of Pagumogonimus skrjabini;Cotylocercous cercaria;Gymnocephalus cercaria.