Father Chrysanthus, Dutch arachnologist (died 1972)

Wilhelmus Egbertus Antonius Janssen, better known as Father Chrysanthus OFMCap, was a Dutch priest and biology teacher. He was known for his studies in arachnology. Initially he was concerned with the spiders of the Netherlands but he became a specialist on New Guinea spiders. Two spider species were named in his honor following his death.

September 1 is the 244th day of the year in the Gregorian calendar; 121 days remain until the end of the year.