686 The American Naturalist. [August, 
of the cells; but we may easily observe that the form and 
size, etc., of the cells have very little to do with the species 
question. The latter depends much more upon the number of 
spores found in the cells, the conditions for the spore-formation, 
and the effect upon the various kinds of sugar. As therefore 
De Toni's monograph can not pretend to give a correct aecount 
of the species known up to date, I have tried to bring together 
the forms in which a formation of spores has been found, with 
description of the various stages in their development. A later 
number of this series, materials for a monograph on the alco- 
holic fermentation, will contain the literature in full. 
Pungaceae. Linné, Gen. 1737, page 327. 
SACCHAROMYCETACEAE. Reess. 
M. Reess: Botanische Untersuchungen ueber die Alkohol- 
gaehrungspilze, 1870. Winter: Die Pilze (in Rabenhorst's 
Kryptogamenflora)I, 1, page 68.  Blastomycetes Frank: Leu- 
nis Synopsis, Botanik, III, page 595. 
Genus: Saccharomyces. Meyen. 
Meyen: Wiegmann’s Archiy. Vol. IV. 2, page 100, 1838. 
Reess, l. c. Winter, l.c., page 69. Joergensen, Die Mikroor- 
ganismen der Gaehrungsindustrie, 1890, page 123. Saccardo, 
Sylloge, VIII, page 916 [De Toni]. Ludwig: Lehrbuch der 
niederen Kryptogamen, 1892, page 210. 
All species unicellular, often adhering together, forming a 
false mycelium. Hyphae or regular mycelia never occur. Cells 
circular, oval, or ellipsoid, often rectangular. Habitat: Caus- 
ing the conversion of glycose into alcohol and carbonic acid, 
and a few other products, most of the species are always found 
in fermenting fluids. Some species are found in other places, 
most of these, however, have not been observed forming spores. 
Further investigation must determine the true nature of the 
latter; probably some of them belong to the Torula-forms in 
the sense of Pasteur. Owing to the general feeling that the 
Saccharomyces are characterized mainly by their faculty of 
spore-formation, I took up only these forms in the present 
synopsis. 
