This is the case as regards the form of Spongilla lacustris found in Lake Baa, Isle of Mull, as regards S. helvetica from the Lake of Geneva, S. moorei from Lake Tanganyika, and S. coggini from Tali-Fu in Yunnan; also as regards the species of Spongilla and Ephydatia found in Lake Baikal, many of the sponges of which are said never to produce gemmules.
"Freshwater Sponges, Hydroids & Polyzoa"
Nelson Annandale