He even says "Hence species may be good ones and differ scarcely at all in any external character".

A few species differ significantly in appearance from most of the family.

Many species and subspecies differ in ways too subtle to pick up through binoculars.

However, this is only a general rule and many species differ.

In addition, the species differ in the shape of their lower pitchers.

The two species also differ in their advertising calls.

As well, the species of diatom may also differ among deposits.

This may be due to the fact that three species generally differ in habit and dietary preferences.

The species of fishes here did not differ much from those already noticed.

Despite superficial similarities to the gray wolf, the two species differed significantly.