中文摘要：

为了研究濒危鱼类稀有白甲鱼（Onychostoma rara）外周血细胞的特征,以采自长江中游沅江水系清水江共计20尾稀有白甲鱼的血液为材料,采用常规方法对稀有白甲鱼外周血细胞的组成、形态、大小和数量进行了观测。结果显示,稀有白甲鱼红细胞数量为（1.75±0.43）×1012个/L,白细胞数量为（5.26±2.09）×1011个/L。在血涂片上共计观察到了5种白细胞,包括淋巴细胞、血栓细胞、单核细胞、嗜中性粒细胞和嗜酸性粒细胞,没有发现嗜碱性粒细胞。这5种白细胞各自数量占白细胞总数的百分比差异较大,其相对数量比例关系为：淋巴细胞〉血栓细胞〉嗜中性粒细胞〉单核细胞〉嗜酸性粒细胞。这5种白细胞的大小也有所不同,其大小关系为：单核细胞〉嗜中性粒细胞〉嗜酸性粒细胞〉淋巴细胞〉血栓细胞。稀有白甲鱼雌、雄个体之间血细胞（含红细胞、白细胞）数量的差异不显著。与已报道的鱼类相比,稀有白甲鱼白细胞的数量明显较高,红细胞数量较多、体积相对较小,这可能与其适应流水生活相关。

英文摘要：

Onychostoma rara,which belongs to Cypriniformes,Cyprinidiae and Barbinae,is an endangered fish species distributed only in the Yuanjiang River of the Yangtze River system and the Xijiang River of the Pearl River system,China. To study the characteristics of the peripheral hematocytes in O. rara,the hematocytes of the species were examined,classified,counted and photographed under the light microscope using WrightGiemsa’s stained smears of peripheral blood from 20 individuals collected in June 2012 from the Qingshui River（ in the Yuanjiang River system located in the middle Yangtze River）,Guizhou,China. The short and long diameters of the hematocytes as well as their nuclei were measured using routine methods,and the experimental data were analyzed with SPSS 17. 0. The results showed that the erythrocytes as well as five types of leukocytes,including lymphocytes,thrombocyte,monocytes,neutrophils and eosinophils,were detected in the WrightGiemsa’s stained smears of peripheral blood in this species. Each of the erythrocytes or leukocytes always had a nucleus,and the erythrocyte and the five types of leukocytes each had different microscopic characteristics. The counts of erythrocyte and leukocyte in the blood of O. rara were（ 1. 75 ± 0. 43） × 1012 cells / L and（ 5. 26 ±2. 09） × 1011 cells / L respectively. Also,the percentage of each type of the leukocytes in total leukocytes was calculated. The five types of leukocytes were much different from one another in quantity proportion and cell size. The percentages of the five types of leukocytes in the blood were： lymphocytes 〉 thrombocyte 〉 neutrophils〉 monocytes 〉 eosinophils,and the sizes of them were： monocytes 〉 neutrophils 〉 eosinophils 〉 lymphocytes 〉thrombocyte. There was no significant difference in hematocyte（ including erythrocyte and leukocyte） counts between male and female individuals. The leukocyte count of the species was much more than that of most of the other fishes studied,and its erythrocyte was also abunda