Polymorphic minerals don't always have the same structure.

晶体通常不具有相同结构。

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， 同样，腕足动来看， 在以前时期也如此。

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.

有一点与个体差异有关， 这非常令人困惑：我指那些被称为“千变万化”或“性” 属，其中种表现出过变异。