Would you rather be weak and fragile or brutish and disgusting? In Wells's vision of the year 802,701, those are pretty much your only options. (If you prefer, skip to the far, far future, where you can be a butterfly monster or a crab monster.) The Eloi and the Morlocks are the two species that have evolved from humanity. The Time Traveller isn't very subtle about their characteristics – he calls them like he sees them:
Now the Time Traveller does make it clear that the Eloi are not just pretty, but also lazy and idiotic. And he even has a few nice things to say about the Morlocks, who, though disgusting and inhuman, "retained...more initiative" and even "some little thought outside habit" (10.4). That's faint praise, but it's enough to show us that the Eloi and the Morlocks serve as mirror images of each other.
This is central to the Time Traveller's theory that the Eloi are descended from the idle rich and the Morlocks from the working poor. The Eloi-Morlock ecology is the centerpiece of the novel's interest in how social class evolves over time: those on top now may find themselves on the bottom later.
It takes a long time for the Time Traveller to finally name these two species – he meets them in Chapter 3 and doesn't name them until Chapter 5. Frankly, it's not clear where he gets the name "Morlock"; he says that "Morlock" "was the name by which these creatures were called" – which raises the question: who is doing the calling?
Anyway, regardless of how he learns them, the Eloi and the Morlocks have very distinctive, attention-getting names – the sort of names whose meanings you might wonder about. It's not entirely clear what they mean, but critics have noted that Morlock sounds a lot like Moloch, which is the name of a Phoenician god associated with child sacrifice in the Bible. ("Mors" is also a Latin root for "death"; if you watch any CSI sort of show, think "rigor mortis.")
There's also a possible biblical root for Eloi. First, Eloi sounds a lot like Elohim, which is a Hebrew word for god. Second, in the Gospel of Mark, Jesus yells out from the cross "Eloi Eloi lema sabachthani?": "My God, my God, why have you forsaken me?" This makes it sound like the Eloi are also named after a god.