中文摘要：

利用活体观察、蛋白银染色及电镜技术对蟹累枝虫（Epistylis eriocheiri）的形态学、表膜下纤维及超微结构进行了较为系统的描述,研究发现：（1）光镜下该种群体双叉分支,活体时虫体表膜柔软,完全伸展时呈长筒状;大核马蹄形,呈横位;伸缩泡单个,斜卧口围缘下方。口围缘纤维上连细密的环状纤维,下接两端较为粗壮,中间细长的纵长纤维,构成了连续的表膜下纤维系。（2）电镜下该种表面具沟、嵴、横纹结构,沟嵴相互交错;口围纤毛花瓣状;虫体表膜层呈齿状,具嵴状突起、泡间微管、表膜孔,胞质层包括内含胞器单一的致密原生质层和富含胞器的疏松原生质层。研究对该种的上述特征在虫体的收缩机制及与其他相似种之间的关系等方面进行了讨论。

英文摘要：

Epistylis eriocheiri Li sp.nov,was isolated from the pincers and legs of Eriocheir sinensis,which were collected from the estuary of Tangxun Lake,Wuhan,China,in September,2008.Living observation and protargol-impregnated technique as well as scanning electron microscopy（SEM） and transmission electron microscopy（TEM） were used to describe systematically the morphology and infraciliature system of these freshwater ciliates,especially their fine structures.As an epibiotic and freshwater species,Epistylis eriocheiri lived in a colony composing of about 100—150 zooids,and it had a dichotomously branch stalk,outside which surrounded a thin layer of shreath.Its whole body was relatively soft and half-transparent;when extending completely,the zooid possessed long ovoid in shape,about（110—170） μm×（50—100） μm in vivo,with ratio about 2：1 of length to width.The organism of the zooid could not be found in the lower 1/3 of the ciliate,thus it looking like spacious and half-transparent;the other 2/3 of the cell,however,contained most of the organisms,such as cytopharynx,contractale vacuole,macronucleus and food vacuole;the cytopharynx extended to the upper 2/3 of the cell,and three shaking peniculus could be seen inside it;contactale vacuole was the only one,about 15μm in diameter,and obliquely locates below peristomial lip;the macronucleus was horse-shoe shape,located horizontally and lied below peristomial disc.The infraciliature system was composed of three kinds of fibers：peristomial lip fibers（PLF）,longitudinal fibers（LF） and circular fibers（CF）.PLF,which was a close circular structure,located on the edge of peristomial disc,and interconnected with CF and LF to form a single fiber system that might provide the mechanism by which the zooid contracted and relaxed;upward PLF located many thin and dense CF,which connected with each other by some little fibers.LF spread through the whole body;the former LF interconnected with PLF to form a dense net-like structure;the middle LF,which w