In regard to the sterility of hybrids, in which the sexual elements are imperfectly developed, the case is somewhat different.

关于性要素发育不完全的杂种的不育性， 情况有些不同。

In the first case the two sexual elements which go to form the embryo are perfect; in the second case they are either not at all developed, or are imperfectly developed.

在第一种情况下， 形成胚胎的两个性元素是完美的;在第二种情况下， 它们要么根本没有发育， 要么发育不完善。

The general sterility of crossed species may safely be looked at, not as a special acquirement or endowment, but as incidental on changes of an unknown nature in their sexual elements.

可以安全地看待杂交物种的普遍不育， 而不是将其视为一种特殊的习得或禀赋，而是作为其性要素中未知性质的变化的附带结果。