Social class is a very important theme of this seminal work, so much so that the Time Traveller draws many parallels between the world that he visited in the future and his own world, based on the common theme of class. The difference however is that in the world of the future that he visits, class has become so entrenched that two new species have been created as a result of these class differences, and the Morlocks and the Eloi are used to represent these two classes and how entrenched the different classes have become, as this following quote reflects:
And this same widening gulf... will make that exchange between class and class, that promotion by intermarriage which at present retards the splitting of our species along lines of social stratification, less and less frequent. So, in the end, above ground you must have the Haves, pursuing pleasure and comfort and beauty, and below ground the Have-nots, the Workers getting continually adapted to the conditions of their labour.
Of course, this quote identifies that at the moment for the Time Traveller in Victorian England there are elements that prevent "the splitting of our species along lines of social stratification." However, he foresees a future where this becomes definitely more and more possible, and the members of the different social classes find it more and more difficult to intermarry, until eventually there are two different and distinct classes who have actually formed two separate species.