PHYCOMYCETES. In the Phycomycetes (alga like fungi) there is a very interesting assemblage of types almost all presenting some alga-like characters, but sufficiently diverse from one an other to suggest that there may have been several points of origin. The most alga-like are the water-molds (Saprolegniales) and the downy mildews (Peronosporales). Here, in ad dition to the ecendeytic body (see CCENOCYTE) , similar to that of the Siphonales among the algm, there are present swimming spores pro duced in terminal spore-cases, and sexual organs (oogonia, and antheridia) very similar to those of Vaucheria. One genus (Monoblepharis) has motile sperms, but in the other types the male organ (antheridium) puts out a tube that enters the female organ (o5gonium) and discharges some of its contents. There is to be noted among these forms a tendency to give up some of the alga-like characters. Thus, in certain of the downy' mildews (Peronosporales) the organ cor responding to the spore-case has ceased to pro duce swimming spores, but has become itself an aerial reproductive cell (conidia, q.v.). In
the water-molds (Saprolegniales) sexuality has so degenerated that the male organs, although frequently present, are rarely, if ever, functional. The Chytridiales include many one-celled forms whose life history presents a continuous alterna tion of motile and non-motile conditions, remind ing one of the life histories of some of the green slimes (Protococcales) among the alga. It has been suggested that the Chytridiales have come from the Protococcales, a group of alga much lower than the ancestors of the downy mildews and the water-molds. It is possible, however, that the Chytridiales are degenerate forms of higher fungi. The common black molds (Muco rales) have less of the algal characters than other Phycomycetes, but the terminal spore-cases and sexual organs recall the downy mildews. The Entomophthorales are a highly specialized group of insect parasites whose relationships are very obscure.