释义 |
blas·to·disc noun also blas·to·disk \ˈ ̷ ̷ ̷ ̷+ˌ-\ Etymology: blast- + disc, disk : the embryo-forming portion of a megalecithal egg with discoidal cleavage, usually appearing as a small disc on the upper surface of the yolk mass — called also germinal disc; see egg illustration |