Hydrozoan eggs can only be fertilized at the site of polar body formation

摘要: Abstract Hydrozoan eggs are normally fertilized at the site of polar body formation. The female pronucleus is just under cell membrane this site. Sperm attracted to and aggregate This paper demonstrates that only region on egg surface where sperm can fuse with egg. has been done by cutting unfertilized into fragments containing formation without region. were added their ability be was assayed noting whether or not they cleaved. Only absence cleavage in lacking cannot attributed inability these attract sperm. Such for several hours while which contain stop attracting a few minutes after fertilization. Cytological studies do show nuclei. lack pronucleus. By using centrifugation it possible move away from centrifuged an appropriate way create but fertilized.