一种淡水缘毛类纤毛虫——沟钟虫的形态学研究

MORPHOLOGY OF A FRESHWATER PERITRICHOUS CILIATE,VORTICELLA CONVALLARIA (PROTOZOA,CILIOPHORA,PERITRICHIDA)

利用活体观察及蛋白银染色技术对一淡水缘毛目纤毛虫——沟钟虫(Vorticella convallaria)的形态学和表膜下纤维系进行了研究。结果表明:沟钟虫的活体个员自然伸展时外形较稳定,并呈明显的倒置钟状,长宽约为50—85μm×40—75μm;口围缘完全外展时为虫体最宽处;伸缩泡一个,较大,位于口围唇下方及口前庭的左侧。胞质均匀而透明,无脂肪滴存在,游泳体呈圆柱形。细胞表面横纹从口围唇到反口纤毛环为74—78条,自反口纤毛环到帚胚为18—24条。大核呈大幅度盘绕的长肠状,两端高度弯曲,纵贯于细胞内。蛋白银制片后表膜下纤维系特征为:虫体纵向纤维稀疏而粗壮,37—42条,似灯笼状;口围盘纤维呈典型的倾斜态分布,并呈放射状排列。第三咽膜(P3)在近口末端处呈明显的分离态,可视为该物种重要的分类学依据。

The morphology and infraciliature of Vorticella convallaria ,collected from both the freshwater ponds near Harbin and Lalin town in China, was described by living and protargol-impregnated specimens. Freshwater Vorticella, zooid in vivo 50-85×40-75μm,stout in shape with a wide highly everted peristomial lip. One contractile vacuole ventrally located at the left of vestibulum and under peristomial lip; one macronucleus is intestine-like, but rather curved in both end. Its adoral end is trans- versely oriented and its abord end extends longitudinally to a recurved extremity,nucleus the ＂S＂ shape seen in many species of VorticeUa;and two micronuclei located at both end of macronucleus respectively. The number of transverse striations from the peristomial area to aboral ciliary wreath （ACW） was about 74-78, from ACW to scopula, 18-24. With 37-42 longitudinal fibers, cell protargol-impregnated is like a lantern. Adstomal end of P3 is rather dispersed than other Vorticella ciliates＇. Peristomial disc fibers （PDF） are oblique radiate assignment, with dichotomous end in each fiber, differing conspicuously from the flower or net-like arrays seen in other species of Vorticella. In conclusion, we consider both of the P3 and PDF as the important taxonomic characters in Vorticella convallaria.