【摘要】 <正> 近年来我国肺吸虫病的防治工作深入开展,引起人们对于寄生虫病流行区的某些淡水螺类,特别是对一些微小螺类的注意。福建及湖南两省1976年分别进行肺吸虫病调查时所采获的,并已查到肺吸虫尾蚴的螺类,经我们分析鉴定为二新种,隶属于觿螺科拟小豆螺属(新属)及小豆螺属。兹分别叙述如下。更多还原

【Abstract】 The present paper deals with two new minute freshwater snails which are foundas the first intermediate hosts of the lung fluke Paragonimus skrjabini Chen. Thenew snails belong to two genera, one of which is new to science, of the family Hydro-biidae. The diagnosis of the new genus and the two new species are given below: Pseudobythinella, gen. nov. Diagnosis: Shell minute, cylindrical, thin, transparent. Aperture ovate, with aprominent tooth in the middle of its inner lip. Operculum thin, corneous, transparent.Central tooth of radula with 5 terminal cusps of same size and 2 basal cusps on thesame level. This new/genus is similar to Bythinella, but the latter genus is characterized by theabsence of inner lip tooth, and by the central tooth of radula with more than 5 termin-al cusps of unequal size and with the 2 basal cusps not on tbe same level. Type species: Pseudobythinella jianouensis Liu et Zhang, sp. nov. Pseudobythinella jianouensis, sp. nov. Diagnosis: Shell cylindrical, minute, thin, transparent, with yellowish periostra-cum. Apex obtuse, whorls 3(1/2), inflated, increase rapidly in height, but slowly inbreadth; body whorl large, occupying about 1/3 of the length of the shell. Suturedistinct. Shell surface smooth, with weak growth lines. Aperture round ovate,slightly expanded outward; peristome continuous, simple, with a black margin. Inner lip with a prominent tooth. Operculum elliptical, thin, corneous, transparent, paucis-piral. Umbilicus slit-like. Radula formula: 5/(2-2); 9; 26--30; 30. Holotype (FJ767701): Length 1.8 mm, breadth 0.8 mm; lenghth of aperture0.9 mm, breadth of aperture 0.8 mm. Jian’ou Fujian; June, 1976. Paratypes: Length 1.6--1.8 mm, breadth 0.8--0.9 mm; length of aperture 0.6-0. 9mm, breadth of aperture 0.6--0.8 mm. Jian’ou, Fujian; June, 1976.Holotype and paratypes are deposited in the Institute of Zoology, Academia Sinica.Distribution: Know from the type locality only.Parasite: Paragonimus skrjabini Chen (lung fluke). Bythinella chinensis, sp. nov. Diagnosis: Shell minute, cylindrical, thin and transparent. Whorls 4-4(1/2), convex,scalariform; body whorl rather large, occupying about 2/3 of the shell length. Shellsurface smooth, with very weak growth lines. Apex obtuse, suture well defined.Aperture round ovate, inner lip without tooth. Operculum ovate, thin, transparent.Umbillcus narrow. Radula formula: 9/(2-2); 26--30; 20--22. Holotype: (HN767702): Length 1.6 mm, breadth 0.7 mm; length of aperture 0.6 mm,breadth of aperture 0.5mm. Lengshuijiang, Xinhua, Hunan; July, 1976. Paratypes: Length 1.6--1.8 mm, breadth 0.6--0.7 mm, length of aperture 0.6-0.9 mm, breadth of aperture 0.5--0.7 mm. Lengshuijiang, Xinhua, Hunan; July, 1976. Holotype and paratypes are deposited in the Institute of Zoology, AcademiaSinica. Distribution: Known from the type locality only. Parasite: Paragonimus skrjabini Chen. The new species is closely related to B. nipponica. Their differences are givenbelow:更多还原