Mr Jemmerling is an egg collector in Great Northern?. He is the owner of the large motor launch Pterodactyl which he uses as a headquarters for his bird and egg collecting expeditions. He collects eggs, and shows the horrified Dick the dried skin of a large bird, a Great Northern Diver, one of three he has collected on this trip. It is like a feathered balloon from which the air had escaped. There could not have been anything deader. He boasts about the Jemmerling collection, the biggest private collectiion in England, probably in the world. Dick realises Mr Jemmerling is a George Owdon, only grown-up and worse (GN9).