But a z-score literally just means how many standard deviations you are away from the mean.

但是 z-score 的字面意思是你与平均值相差多少标准差。

By a monstrosity I presume is meant some considerable deviation of structure, generally injurious, or not useful to the species.

我推测的怪物是指结构上的一些相当大的偏差， 通常是有害的， 或者对物种没有用处。