Let me give the context first. Rainsford and his friend, Whitney, are talking about hunting. In particular, they are talking about hunting jaguars. Both men are excited about the prospects of hunting jaguar. Presumably they are en route during this conversation to hunt jaguar. Rainsford says that hunting for jaguars is the best sport in the world. Whitney, jokingly, says, "not for the jaguar."
Rainsford retorts by saying that Whitney is not philosopher. Moreover, he say that jaguars have no feelings or thoughts. Then, ironically, Rainsford gives his philosophy. Here is what Rainsford says:
"Nonsense," laughed Rainsford. "This hot weather is making you soft, Whitney. Be a realist. The world is made up of two classes--the hunters and the huntees. Luckily, you and I are hunters. Do you think we've passed that island yet?"
The great irony of these words is that Rainsford will fall off his boat and become stranded on an island, where he will meet the mad, general Zaroff. When he does, he will become the huntee.