Say what you will about Wells; he doesn't cop-out on his endings (unlike some TV shows we could mention).
Let's start by saying that Moreau's island isn't technically called Moreau's island. As Montgomery points out, the island doesn't have a name (2.26). Montgomery never says why this is, so the question remains open. Why do you suppose Moreau or any of its inhabitants never named the island?
As for the place itself, it's an island in the Pacific and was born out of a volcano, meaning it's probably covered in lush tropical forest and hot springs thanks to that volcanic soil. This origin also means it suffers from the occasional earthquake and steam pockets (15.6). In short, it's just like a Hawaiian island; only the luaus are replaced with the experimental ravings of a mad genius. There are still worse places to take a vacation.
Moreau's island embodies a dual nature. One the one hand, it's beautiful and lush, vibrant with life. On the other hand, the geological features making it lush, such as the whole volcano thing, also create a volatile and dangerous place to live. This dual nature extends beyond the land itself to the people and Beast Folk living on the island.
We'd say more on the island's allegorical nature here, but hey, that's what our other sections are for. You can head over to our "Symbols, Imagery, Allegory" section to check out the deeper implications of the island. You can also go to our "Genre" section to learn more about the dystopian nature of the place and the time in which it is set. Either way, the discussion lives on.
The Pacific Ocean as a setting doesn't really give us much to talk about in terms of set dressing. It's the ocean. It's big and blueish and there's the "water, water everywhere but not a drop to drink" thing going. And, um, there are ships which people use to sail on it.
Still, the Pacific Ocean is super important to the story. Here are some things to note. When the Lady Vain sinks, Prendick is thrust into the ocean where his fellow travelers consider eating each other before fighting to the death (like animals, perhaps?). Then aboard the Ipecacuanha, Prendick witnesses a zoo type scene with the deck "littered with scraps of carrot, shreds of green stuff, and indescribable filth" (3.7). Then there's Captain Davis, who threatens to cut out M'ling's "blasted insides" should he go to the wrong part of the ship (3.33).
All of these aspects of the Pacific foreshadow what is to come on Moreau's island. The Ipecacuanha has given up her manmade order and reverted to a more natural chaos. Human decency has become dog-eat-dog, and the Captain's creation of his own rules reflects what Moreau has done to his island. In a way, the Pacific serves as a sort of portal for Prendick, one that takes him from the civilization of London society to the weird grotesqueness of Moreau's island society.
England—particularly London—exists as a setting mostly in the imaginations of our characters. In their minds, it's everything that Moreau's island is not, namely civilization and all the perks that come with it.
Montgomery remains homesick for the city, gossiping with Prendick about the fashions and news (4.4). For Montgomery, it's a place awash with that warm nostalgic glow. Prendick views London as a goal. Like Dorothy in Oz, his mantra throughout his adventure is, "There's no place like home; there's no place like home." For him, London is a safe haven, a way to rid himself from the chaos of the Moreau's island. He does eventually make it back to London in the very last chapter, and what does he discover…?
Well, you'll have to read the book to find out, and then feel free to check out our "What's Up With the Ending?" section for more awesome discussion. Hint: Thomas Wolfe was right. You can't go home again.