The result of the screening of lectins on 28 species of marine shell fishes(mollusks) showed that 10 species (Tapes philippinarum, Cyclosunetta menstrualis, Neptunea arthritica cumingii, Omphalius pfeifferi carpenteri, Chlorostoma argyrostoma turbinatum, Chiorostoma argyrostoma lischkei, Semisulcosira corea, Neptunea polycosta, Babylonica japonica, Noverita didyma) were present hemagglutinating properties to human A, B, and O group, and animal blood erythrocytes. A new lectin from Tapes philippinarum. was isolated and partially characterized. The lectin was purified by (NH$_4$)$_2$SO$_4$ precipitation and ion exchange chromatography on DE 53 column. Six fractions were obtained from DE 53 column by salt gradient elution but only 0.3M, and 0.4M NaCl fraction had strong lectin activity. On its 0.3M NaCl fraction, purity was identified by polyacrylamide gel electrophoresis. This lectin was inhibited by N-acetyl-D-galactosamine. It seems that two kinds of lectin react as antigen by immunochemical studies.