Adam
This English zoologist is a smooth-talker who seduces Madelene into moving with him to London. Although this character is named after the first man, his "Eve" ends up with a hyper-intelligent ape. Apparently, the life Adam put together for Madelene was not impressive enough to make her stay. His work is fascinating to him, but it often occupies him entirely, and Madelene is not happy as a kept housewife. Adam gets left for an animal.
Madelene
Madelene is a Danish girl living in Copenhagen when one day, she meets Adam who invites her to live with him in London. When she says yes, they board a voyage to London on the Thames, and she comes in contact with a smart ape who can speak. Her life in London is disappointing at best, so she leaves Adam for Erasmus, the Ape.
The Captain
Although this is only a minor character, he is fascinating. He changes his name often, but these days, he goes by "Bally," whatever that means. He is a smuggler who has secretly abducted an ape from DNA experiments that made it hyper intelligent. When the ape gets loose, this captain doesn't have a shot of catching him. Hilarious hijinks ensue.
Erasmus
When Adam finally confronts the ape in question, the ape introduces himself as Erasmus. He has taken that name to bring attention to his uncanny ability to consider religious philosophies. He is quite a theologian, but he is also extremely strong and coordinated. Madelene loves him.