WITH NOTES OX OTHER SPECIES. 99 



desultory way. But the fact that of the thirty-four established European species, 

 sixteen are here included, while five species previously unknown are described, shows 

 what we may expect as the result of thorough exploration of many localities. It is 

 hoped that the present contribution may serve to stimulate such exploration. 



HiSTOKICAL. 



The first references to any of the Saprolegniaceue appear to have been those of 

 Ledermiiller in 1760, of Wrisberg in 1765, and of Spallanzani in 1777. By these and 

 later writers for a long time they were regarded as Algae and were described by most 

 under the generic name Conferva^ which included, in its Linnsean application, the fila- 

 mentous aquatic plants, generally. The earliest binomials appear to be those of the 

 Flora Danica (1780), Byssus aquatica, and of Schrank (1789), Conferva piscium. Pre- 

 vious writers had seen these fungi on flies in water, but in Schrank's name is the first 

 record of their occurrence on fishes. The earliest figures are those of the Flora 

 Danica (1780), of Dillwyn ('09), and of Lyngbye ('19). As the early observers saw 

 and figured only the sporangia, it is impossible to refer their plants to the proper 

 species. It can only be said that the names Byssus aquatica Fl. Dan. and Yaucheria 

 aquatica Lyngb. refer to species of Aclilya. Dillwyn figured the Conferva lactea of 

 Roth (1789), which is i-ecognizable as our Leptomiius lacteus Ag. Gruithuisen de- 

 scribed ('21) a fungus on the remains of a dead snail, and for the first time figured 

 the escaping zoospores of Saprolegma, though without cilia. This form he called 

 Conferva ferax, sl name which was subsequently used promiscuously by many 

 authors for any of the larger species of this family. It was first applied to a distinctly 

 characterized form by Thuret ('50), though without an understanding of the real 

 specific differences among these plants. Carus next ('23) described a fungus on 

 salamander larvae, with spores collecting in a globe at the mouth of the sporangium, 

 w^hich he called Hydronema. He observed several characteristic features in the 

 development of the form, and recognized its points of difference from Gruithuisen's 

 fungus. In an appendix to Carus' paper, IsTees von Esenbeck ('23) established the 

 genera Sajjrolegnia and A.cMya on the distinctive differences in the escape of the 

 zoospores which we recognize as their most salient characters, to-day. He called 

 Gruithuisen's fungus 8. molluscorum, and Cams' form A. prolifera / but he appar- 

 ently did not know the sexual organs, and it is impossible to identify the species 

 intended by him. A year later, Agardh ('24) included in his genus Leptomitus all 

 described Saprolegniacem under the names Ij. clavatus, prolifer, and ferax, grouping 

 the forms of earlier writers rather according to substrata than by structure, and mix- 



