Otto Philipp Maas (born 30 July 1867 Mannheim; â 17 March 1916 Munich) was a German zoologist and university professor of evolutionary history.
Maas studied zoology and medicine at the universities of Munich, Strasbourg, and Berlin, and received his doctorate in 1890 with a thesis on the development of the freshwater sponge. In 1894, he became a professor of zoology and evolutionary history at the Ludwig Maximilian University of Munich. In 1902, he was promoted to associate professor in Munich, and in 1908, he was given a paid personal teaching position in comparative and experimental evolutionary history, as well as a teaching position in general zoology at the Royal Bavarian Academy of Agriculture and Brewing in Weihenstephan. In addition to the general and experimental history of animal development, Maas was mainly concerned with the research into cnidarians and in this area was the first to describe the umbrella jellyfish Nausithoe albatrossi (Maas, 1897) and the hydrozoa Euphysora bigelowi - now Corymorpha bigelowi (Maas, 1905), which he named in honor of the US zoologist Henry Bryant Bigelow.
On 8 March 1906 Maas was admitted as a member of the Imperial Leopoldine-Carolinian German Academy of Natural Scientists under the registration number 3208 in the Zoology and Anatomy section.