文蛤 (hard clam, Meretrix lusonia Roding) 和台灣蜆 (freshwater clam, Corbicula flumineaMullar) 皆為本省重要的養殖貝類，養殖過程中常因養殖環境惡化，使得產量極不穩定，造成嚴重的經濟損失。許多因素皆可造成貝類死亡與生長遲緩，其中微生物感染亦包括其中。因此，如何降低死亡與增加產量為當務之急。本實驗目的在於研究兩種二枚貝類 (文蛤與台灣蜆) 血淋巴球之分類與形態觀察。利用percoll 梯度離心並輔以光學與電子顯微鏡觀察，結果顯示文蛤之血淋巴球可分為3 種血球：嗜鹼性顆粒球 (density: 1.055 g/mL)、嗜酸性顆粒球 (density: 1.029 g/mL) 及透明血球 (density: 1.018 g/mL)。於台灣蜆之血淋巴球亦有類似之嗜鹼性顆粒球 (density: 1.067 g/mL)、嗜酸性顆粒球 (density:1.047 g/mL) 及透明血球 (density: 1.020 g/mL)。這些結果對於貝類血淋巴球之研究，可以此為基礎，並進一步地研究貝類之各類血淋巴球之細胞性免疫的功能與作用，以及進一步地瞭解其非特異性免疫的特性。因此，基於以上對貝類血淋巴球的初步研究，希望對於未來貝類疾病預防及防治上能有所助益。

Both of hard clam (Meretrix lusonia Roding) and freshwater clam (Corbicula fluminea Mullar) are important cultural shellfishes in Taiwan. During cultural period, environmental deterioration often induced the unstable production of shellfish and caused serious economic losses. Therefore, how to reduce the death of clams and increase production is a priority. Many factors like as microbial infection can cause deaths and growth delay of shellfish. Therefore, how to decrease the mortality and increase the production of shellfish is a priority. Aim of this study is to study the classification and morphology of shellfish (hard clam and fresh clam) haemocytes. By percoll gradient centrifugation and supplemented by optical and electron microscopy experiments showed that haemocytes of hard clams can be divided into three cellular kinds: basophilic granulocyte (density: 1.055 g/mL), eosinophilic granulocyte (density: 1.029 g/mL) and transparent cells (density: 1.018 g/mL). Fresh clams also showed the similar results: the basophilic granulocyte (density: 1.067 g/mL), eosinophilic granulocyte (density: 1.047 g/mL) and transparent cells (density: 1.020 g/mL). These results for the future studies in shellfish haemocytes can be used as the basis then perform the further study of cellular immunity and non-specific immunity of these cells. Therefore, we hope that disease prevention and control of the shellfish can be helpful in the future based on the above preliminary investigation of shellfish haemocytes.