Polymorphic minerals don't always have the same structure.

多晶体通常不具有相同的。

Genera which are polymorphic in one country seem to be, with a few exceptions, polymorphic in other countries, and likewise, judging from Brachiopod shells, at former periods of time.

除了少数例外， 在其他国家似乎也是多态的， 同样，腕足动的壳来看， 在以前的时期也是如此。

There is one point connected with individual differences which is extremely perplexing: I refer to those genera which have been called " protean" or " polymorphic, " in which species present an inordinate amount of variation.

有个体差异有关， 这非常令人困惑：我指的是那些被称为“千变万化”或“多态性” 的属，其中种表现出过多的变异。