The most prominent feature uniting Dimetradon with mammals is a number of holes in it's skull.

将 Dimetradon 与哺乳动物结合在一起的最显着特征是它的头骨上有许多孔。

Amniotes can be subdivided into several groups based on the number of holes or fenestra in the skull.

羊膜动物可以根据头骨上的孔或孔的数量细分为几个组。

Tooth shape, bipedal or quadrupedal, number of holes behind the eye in the skull, and so on.

牙齿形状、双足或四足、头骨中眼睛后面的孔数等。

Primo, the cyclostomes, whose jaws are fused into a flexible ring and whose gill openings are simply a large number of holes, an order consisting of only one family. Example: the lamprey.

第一目，圆口鱼，鳃合成为一个转动的圈环，鱼鳃开合有许多小孔，这一目只有一科。类型：人目鳗。