Does it mean variety? If so, why not say variety at once?
Does it mean species? If it do, one of the two phrases is superfluous.
In simple truth it means either or neither, as the case may be; and is convenient or superfluous according to the views of the writer who uses it.
If he believe that groups and classes like the Negro, the Hottentot, the American, the Australian, or the Mongolian, differ from each other as the dog differs from the fox, he talks of species. He has made up his mind.
But, perhaps, he does no such thing. His mind is made up the other way. Members of such classes may be to Europeans, and to each other, just what the cur is to the pug, the pointer to the beagle, &c. They may be varieties.
He uses, then, the terms accordingly; but, in order to do so, he must have made up his mind; and certain classes must represent either one or the other.
But what if he have not done this? If, instead of teaching undoubted facts, he is merely investigating doubtful ones? In this case the term race is convenient. It is convenient for him during his pursuit of an opinion, and during the consequent suspension of his opinion.
Race, then, is the term denoting a species or variety, as the case may be—pendente lite. It is a term which, if it conceals our ignorance, proclaims our openness to conviction.
Of the prospective views of humanity, one has been considered. But there are others of at least equal importance. Two, out of many, may serve as samples.