Norman Platnick was having no luck with millipedes.

He was 16, a senior in college (yes, he started at 12) and was interested in a fellow biology student named Nancy, who was “very interested in millipedes,” he recalled.

It was 1967, and they were taking a class on arthropods and needed specimens. But, he said: “I was a lousy millipede collector. There would be nothing in my jar but spiders.”

He examined one of the spiders “for a few hours,” he said, and was able to identify it as part of the genus Cicurina. “So I said: ‘That was kind of fun. Let me try another.’ And I just never stopped.”

Dr. Platnick would become a world authority on spiders — and the husband of Nancy Stewart Price. He died on April 8 in a hospital in Philadelphia at 68. The cause was complications from a fall in his home, said his son and only immediate survivor, William Platnick.