Abstract:The fertilization experiment of Tegillarca granosa (♀)× Scapharca subcrenata (♂) was carried out three times at Qingjiang Field Research Station of Zhejiang Mariculture Institute in July, 2009. Consecutive cytological observation of fertilization and embryonic development of Tegillarca granosa (♀)× Scapharca subcrenata (♂) were conducted using both optical microscopy and fluorescence microscopy (Hoechst 33258 staining). The results show that sperm of S. subcrenata can attach to the surface of T. granosa eggs rapidly and the acrosomal reaction can be achieved successfully. Subsequently, the interspecifc sperm activated the meiosis of T. granosa egg and induced the releasing of PB1 and PB2. Then, the male and female pronuclei fused into zygotonuceus and the cleavage began subsequently. The rate of crossing fertilization was approximately 60.2％,and the early embryogenetic development of T. granosa (♀)× S. subcrenata (♂) was slower compared to those of intraspecific control groups, respectively. During the whole development process, the blastula stage was relatively long compared to that of control groups and the embryo was obviously abnormal, which may only reach trochophore stage and died before D shaped larva stage. Trochophore larva of T. granosa (♀)× S. subcrenata (♂) were found to keep excessive cilia growth. In addition, polyspermy and multiple separations were observed in this experiment
