The case most frequently insisted on by palaeontologists of the apparently sudden appearance of a whole group of species, is that of the teleostean fishes, low down, according to Agassiz, in the Chalk period.

古生物学家最常坚持的一整群物种明显突然出现的案例是硬骨鱼类，根据阿加西的说法， 在白垩纪。

Some few families of fish now have a confined range; the teleostean fishes might formerly have had a similarly confined range, and after having been largely developed in some one sea, have spread widely.

现在一些少数鱼类的活动范围有限；硬骨鱼类以前可能也有类似的局限性，在某个海域大量发育之后， 分布广泛。