They move closer. The forest, Aronnax can see, is made up of "tree-like" plants with bizarre branches. Everything grows straight up, and any attempt to bend the branches or even the blades of grass on the ground is pointless.
"It was the realm of the vertical" (1.17.3), Aronnax thinks.
The place is so packed with life that even Aronnax, a scientist, has trouble telling the difference between plants and animals. He spends a while making sense of the strange life that surrounds him.
An hour later, Nemo stops the expedition again, and they take a breather. Aronnax is surprised to find that he's not very hungry, even after walking for four hours. Soon they're all asleep.
When Aronnax wakes up, the sun is already setting.
Suddenly, Aronnax sees a sea spider. He shudders. The sailor smashes the sea-bug with his gun. Aronnax realizes that there are probably lots of even scarier things moving all around him.
Nemo continues moving onward, downward, deeper into the ocean depths. The hunters turn on their lights.
Eventually they come to a big wall of rock. It's an undersea cliff: the edge of Crespo Island.
Nemo stops the expedition and they head back in the other direction.
Without warning Nemo pulls out his rifle, aims, and shoots something in the distance. He's bagged himself a sea otter.
The sailor picks up the otter and carries it over his shoulder. Now that's hunting.
Soon after, once the hunters have reached shallower water, the sailor aims up in the air and takes out a bird flying up above. (Never mind that shooting something through water is pretty darn hard because the water bends the light and makes it tough to judge the real position of the thing. You've probably noticed the same effect when drinking stuff with a straw.)
They all keep walking. Then, Nemo pushes Aronnax to the ground and lies still on the ocean floor.
Aronnax looks up and sees two huge sharks swimming nearby. Luckily, the sharks leave, and everyone makes it back to the Nautilus with all of their limbs intact.
Aronnax changes out of his suit. Dazed from hunger, fatigue, and wonder, he stumbles back to his room.